I have 2 ceiling lights on one switch-I'm enclosing one of them by making that area into a closet-can I put a simple old pull cord light on the one in the closet ? How can I keep power to it so it has power all the time so I can operate it from pull cord and the other one still operates on the wall switch(wall switch is a two way)??

You can't do what you want to do unless you are willing to run new cabling back to the switch box or another power source. The switch would have to be on 24/7 for the power to reach the pull chain. If the switch is OFF you can pulll the cahin all you want and nothing will happen. This new enclosed area needs its own power independent from the other light/switch

I would check inside the closet light box for a contant hot passing through the box, connect pull chain fixtue to that, switch should operate other lite with no other wiring.
If a constant hot is not in the box, and wiring is in conduit, you may be able to push or pull another wire.