I'm reading these different websites that are saying Constantine joined two different religious figures at the Council of Nicea, Hesus and Krishna; this combination eventually morphed in Jesus Christ. Is there any truth to this?
There's zero evidence for it. If you point to some actual claims I'm happy to work through them, but first up I would say:
Jesus is a well established 'figure' well before Constantine. You have 3 centuries of documentation by Christians writing about who they think Jesus is. The level of conspiracy required to attribute Jesus to Constantine is very high.
There is no evidence to suggest Hindu influences in Roman-Era Christendom.
There's no evidence to suggest this kind of influence by Constantine.