No True Scotsman

Is it a No True Scotsman, to say someone is not a scientist? Like, I once debated someone who clearly didn't have any education in physics nore any form of natural science, yet he claimed he knew a lot of stuff based on videos on youtube he watched. Then he went in to say he's a scientist just because you just need to use the scientific method, to be a scientist.
So the definition of a scientist is ''a person engaging in a systematic activity to acquire knowledge that describes and predicts the natural world.'' (wikipedia), meaning someone who uses the scientific method.
Since science like Physics, Chemistry etc. use the scientific method for their basis of gaining knowledge, does that mean a person who claims to be a scientist (without having any knowledge in these spheres) can be called not a real scientist?
In religion there is no claim in their books ''if you do this you're not a real...'', which means that a religious person using the ''no true christian would ever do this'' for example, means they are using a No True Scotsman. But when it comes to science. Can a person be called a scientist, If they haven't had any expirience in any form of natural science, but just use the scientific method? And Its also another discussing, whether they actually use it properly or not.

This is not the No True Scotsman , it does not quite fit. What this appears to be is an argument over the exact meaning of a word. In 5th grade, I won the "junior scientist award." Was I really a scientist? That would be a stretch, but I did apply the scientific method to a problem. In common usage, a scientist is someone with a degree in a field of science.

{date-time stamp}Monday, Jun 26, 2017 05:19 AM{/date-time stamp}

I was not satisfied with my answer above because I felt I did not explain enough. A key component of the No True Scotsman is rejecting what is overwhelmingly an accepted definition/example out of the desire to not accept one specific case into a group. In your case, a very broad definition of "scientist" is being used that can include children at science fairs. If you want to avoid being accused of this fallacy and don't feel like arguing semantics, avoid debating labels and make the distinction between how your opponent is using the label and how it is commonly used. For example,

If you want to call yourself a scientist, that is your prerogative. However, realize that the vast majority of people call themselves 'scientists' also have an advanced degree in a field of science. This is categorically different than watching a handful of YouTube videos. The point being, you simply calling yourself a 'scientist' does not lend you any credibility... at least not with me.

Anthony Flew, a world famous atheist who went deist, coined the No True Scotsman fallacy. I personally don't think the reasoning is completely applicable to Christianity or Christians because you can't be a Christian by birthright or place of birth. Whether this applies to the behavior of a person who may be a Christian or not seems questionable because only Jesus decides who is a true Christian if he even recognizes such a thing. That's based on biblical theology because the Bible actually says only Jesus can judge the true reins of the heart meaning people can't really decide what qualifies as "a true Christian".
As far a what a scientist is, it all depends on how strict you want to be with the term. If the definition leaves room for it to simply apply to anyone who uses the scientific method, like you say, then it seems most everyone is a scientist. The popular use of the term usually only applies to someone who has some sort of degree in science and then the level of degree determines how reliable the information, or the interpretation of informstion, should be considered I believe. Ex. Most people can fill a balloon with helium and then claim through the scietific method they've shown helium rises and is lighter than oxygen etc....That's the scientific method right? Ok I'm rambling and probably didn't help.

"Then he went in to say he's a scientist just because you just need to use the scientific method, to be a scientist."

Actually you need peer reviewed research to have a valid scientific opinion and your accreditation must come from a legitimate institution.

Google university doesn't qualify.

People love to use the old " well this scientist or this expert said such and such therefore it must be true"

I would counter with asking if his opinion is shared by the scientific community through widely accepted consensus or whether there is peer reviewed research that supports his opinion.

A scientist can make a claim that is nothing more than his informed opinion, albeit probably more informed than from a lay person, it can still be questioned.

Example

This scientist said building 7 looks like a controlled demolition , therefore 911 was an inside job.

Unless this scientist was part of the group of engineers that directly examined the evidence, I would say that this claim is not acceptable evidence of an inside job and i would need more to accept the inside job conclusion.

I think everyone gave great answers to your question. I would only like to add some practical perspective. If conversation is fast paced, often times it's hard to explain the details of widely accepted definitions. However sometimes answer is just that simple.
I looked up definition of scientist on several most popular dictionaries which in many ways represent what people expect one to be when the person is called scientist.

An expert in science, especially one of the physical or natural sciences.
dictionary.com

a person learned in science and especially natural science : a scientific investigator

Merriam-Webster

A person who is studying or has expert knowledge of one or more of the natural or physical sciences.
Oxford Dictionary

an expert who studies or works in one of the sciences
Cambridge Dictionary

someone who works or is trained in science
Longman Dictionary of Contemporary English

So in practical terms you could mention that most of the dictionaries and general public define scientist as someone who has an expertise, education, training and experience in science. Scientific method is very important tool, but not the whole of the science . They have to be an experts not only in scientific method, but also in previously developed knowledge base of science. So using these common definitions you could say that it is NOT enough to be an expert in scientific method, you have to be an expert in SCIENCE.