Is it safe to freeze leftover chicken that was originally refrigerated vacuum se...

Purchased refrigerated vacuum sealed chicken, cooked it and wanted to freeze leftovers, is it safe

Since you state that you have cooked it, of course you can freeze it.

If you cooked it safely the potential pathogen load has been largely eliminated and the "food safety clock" resets.

A handy official chart. Safe refrigerated storage time listed is quite short for fresh poultry at 1-2 days, while refrigerated cooked leftovers are listed at 3-4 days, and a note at the top of the chart states that the 4 month recommendation for frozen leftovers is for quality only, not safety, as it is safe indefinitely once cooked and then frozen.