I doubt you could make anything substantial on it. There are actually rules about how much can charge and it’s not that much. You also have to pay to become a notary.
The pay is minimal and I doubt there is that much need for it that you could make decent money. Unless you are hired by a law firm or someplace that constantly needs things notarized.
you can charge more if you travel. sometimes the person has several signatures to notarize and you can charge for each one. but yes, it's good to add to your resume, not as a full time job