Basically I was trying to see or figure out ways to find out what my last name means.
I don't know if you have tried a search using Google, or similar. I could find nothing on the NOTHEISEN surname, so wouldn't expect any tool provided by FamilySearch to do any better. Maybe it's for the best that you can't find a published meaning of your last name. Many individuals have complained here that the meaning provided for their name is totally incorrect. In fact, it would probably be very common for a surname to have multiple meanings, depending on its origin and possible variants. Take just one example of the name LEE - I don't expect it has the same meaning to someone in China to a person of English descent! A prominent genealogist here in England advises any definition in a surname dictionary to be viewed with scepticism.
"Many individuals have complained here that the meaning provided for their name is totally incorrect."
I've just been sent a circular email by FamilySearch telling me what my surname means, and its the same wrong story again. Has anyone successfully engaged with FS to get them to correct a wrong meaning?
To answer your question:
Has anyone successfully engaged with FS to get them to correct a wrong meaning?
When the Ancestors (now About) pages first came out I engaged FamilySearch about bogus origin stories for certain surnames and was told there is nothing FamilySearch can do; the information is a third-party product FamilySearch has licensed.
FamilySearch is echoing primarily the content of a specific USA-centric book. The book is identified in the mobile app, in the Find tool: Dictionary of American Family Names (2003, 2006). Unfortunately, if there is no published research that book includes speculation, sometimes quite fanciful. I have also seen citations to Dictionary of Family Names in Britain and Ireland (2016).
So, the answer is to do your own research study, get it published in a relevant journal such as Journal of One Name Studies, and send a reprint to editors of relevant books for inclusion in future editions.
For many personal names I find it useful to consult the website forebears.io. Wikipedia also can be helpful.
@Nathaniel Simon Notheisen
You are asking exactly the question that leads many family historians and genealogists to join a surname research society such as the Guild of One Name Studies and/or begin a surname study.