The trigger wire for the alternator (what tells it to power up when the ignition is on) goes through the idiot light in the dash. No bulb, no charge. Some vehicles won't charge with an LED bulb in that spot. Nissan included a resistor in parallel to keep the alt working if the bulb burns out, but it's no help in this situation because it's in the cluster too. Page SC-12 of the '98 manual has diagrams of the circuit and the two cluster plugs. Looks like there's a white/black wire in one of the plugs going to the cluster from key-switched + and a yellow/black wire in the other plug going to the alt. Rig up a temporary idiot light with a 194 bulb or similar with one wire to pin 12 and one to pin 43, and that should get it working until you get your cluster back. Don't just jumper the two without the bulb! That would create a dead short when the bulb is supposed to be on (key on/engine off, so, every time you go to start it), which would probably pop the 10a fuse (which powers quite a few other systems as well), and might not make the alt happy either.
I didn't know that Nissan split the starting/charging systems off from the electrical section in '98. I was looking for the alternator wiring in EL and it just wasn't there. I thought I'd left a few marbles somewhere!