Hello! I tried to import monsters models from darkplaces QHD1.31 pack to nQuake package, but I don't know which files to copy and where to put them. I even copied all files from QHD_v1.31/Quake HD Pack/id1/ to nQuake directory (ezquake, id1 and qw directories) but it didn't work. I googled it and searched this forums, with no luck. If anyone knows if it is even possible to put darkplaces' QHD monsters models in nQuake package, and how to do it, please answer.

I don't know what that 1.31 HD pack is, but I tried using Rygel's texture pack for Darkplaces ( that you can find here in 3 parts ), and I had to use a clean ezquake install, all the pk3s in nquake gave me lots of bugs.
But if you're talking about MODELS and not textures, most models form those packs are .md3 which won't work with ezquake, you'll have to use Darkplaces for that.