Answering as simply as possible, hope it translates ok.
Here are your possible setups and software compatibility:
1) PLX-1000 x 2, DJM-450. (Software: rekordbox only.) *Note: You also need RB-VS1-K Control Vinyl x 2
2) PLX-1000 x 2, DJM-900NXS. (Software: rekordbox/Traktor.) *Note: You also need RB-VS1-K Control Vinyl x 2 for rekordbox or TRAKTOR SCRATCH Control Vinyl x 2 for Traktor.
3) XDJ-1000MK2 x 2, DJM-450. (Software: rekordbox only.)
4) XDJ-1000MK2 x 2, DJM-900NXS. (Software: rekordbox only.)
5) PLX-1000 x 2, XDJ-1000MK2 x 2, DJM-900NXS. (Software: rekordbox only.) *Note: You also need RB-VS1-K Control Vinyl x 2
The PLX-1000 is a turntable.
I do not see a Xdj 1000 nxs2, I think you mean the XDJ-1000MK2. This is a controller made to feel like a CDJ.
For turntables, you will need control vinyl to play music with software.