you'll definitely want stereo mics... so one probably won't do.... but, a decent stereo pair in a good sounding room with PROPER PLACEMENT could sound quite OK...
i think you'll be fine if you get one more NT4, or some other matched stereo pair. put your players in the room and the two mics on stands... then feed it into the recorder, put it in record-ready mode and put a good pair of headphones on. then, with the headphones on and the musicians playing, move the mics around on their stands and listen to how the placement of them change the sound. find a sweet spot, and record.
you'd be even better off with two sets of stereo mics... one set closer to the musicians and one set far away for the room tone all recorded onto 4 track so you can play with the relationship later..
but, if you cant' get 4 mics.. at least get two and spend some time experimenting with different placements.