Broken nipple OT

[chucks70]

Here goes again with the 90 olds cutlass 3.1 v6. Heater hose that comes out from under the temp. sensor which is in the manifold under the thermostat. Had a leak in this area. No sign of leak from the sensor, removed it to get to the nipple for the heater hose. Just a light turn with the wrench and I had half a nipple out. The rest is stuck in the manifold, broke off flush. Any ideas on how to get it out without dismantling the top of the engine. Not much room to work. Help please