Do Wookiees seek revenge? (Excepting the Wooks gone bad in the EU past and present.) That’s a good question. Chewie would look nasty just killing Kylo in cold blood. I can’t see him doing it unless Kylo is about to kill someone, and it’s the only way to save them.
It’s equally possible Kylo turns away from the dark side long enough to do something good, but dies in the process. Like Grandfather, like Grandson. Think about it, won’t you? 😉