I am working on creating a line-bot from a book and it calls for a 6v, 1AH battery. I have these NiMh AA batteries that are rated at 2.3AH, 1.2v. Is there a way to set these up safely for the bot? What happens if I use too much current but the correct voltage?
You should be able to connect in series 5 of those AAs to reach 6V. You should be fine with your 2.3 Ah batteries. The Ah rating is a measurement of the battery capacity. So your AAs can deliver 2.3 amps for 1 hour. It has nothing to do with how much current the battery actually supplies to the robot.
You would require five of the 1.2 volt Ni Mh batteries to produce 6 volts for your line-bot. The set of 2.3 AH (or 2300 mAH) batteries would run your line-bot about 2.3 times as long as the 1 AH (or 1000 mAH) batteries. (note that 1 AH = 1000 mAH)
As mentioned by others, the AH rating of a battery is an indication of the energy available from the battery. Your load will only draw the current it requires, regardless of the AH rating of the battery (providing the battery voltage is correct for the load).