In this scenario, both Denver and Cleveland have to decide if they value Murray's potential upside greater than Harris' current production and upside. Harris is certainly the more balanced and better player now, and he fits both teams better (for example, Murray is essentially a poor/young man's Irving with a similar game, so is somewhat redundant if staying), but Harris is about to be expensive, and his ceiling isn't what Murray's is.
The Nuggets have other pieces than Chandler they could include to match salary, like Faried because, you're right, they really can't afford to give up Chandler from a positional perspective.
Harris or Murray (not both), Faried, pick(s), and perhaps one or two of the other young Nuggets who are a notch below Murray and Faried (Mudiay, Hernangomez Lyndon, Lyles) is the most I would want them to give up and seems fair, but I am a Nuggets fanboy so I could be overvaluing the current players.