the only reason i can think of for a 403 here is that you have an HTML and a folder with the same name. The browser opens the folder instead of the HTML and tries to open the folder's index but the index is actually the root directory, so nginx won't let it. If you rename the HTML it should work.
LETS FUCKING GOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
Bro finals made me wanna 😔🔫 (/j)