The president cannot incite a coup when he already is the president. That would be a coup against himself! If you think this was a coup attempt against the incoming Biden administration, it depends whether Biden was lawfully elected or not. Many of us think that there was likely massive voter fraud and that Trump would have been the rightful winner absent that. If so, then certification of Biden as president would represent a kind of coup in its own right. But nothing justifies rushing the capitol. Violence solves nothing. I think there is plenty of evidence of "irregularities", but the only way to "prove" voter fraud would be to have a forensic audit of the counties in question. But aside from a few small counties (Antrim, Michigan and maybe a small one in Georgia) I don't believe it has been done.