Q: Sticking Accelerator Pedal - 2006 Nissan Altima

I went to autozone to get a new battery installed just a few days ago. When I got in the car to go to the store about a day after they installed the new battery, I tried to turn the key and at first all the lights went dead. I checked under the hood and it turns out the "+" wire on the battery was loose and had come almost completely off. Frustrated, I plugged it back in and tightened it myself. When I tried to turn the car on again, the engine begin to rev(accelerate) on its own and the gas pedal became stuck halfway down. No engine lights or anything else have turned on since the issue. Could the problem be due to the fact that they installed the battery wrong? When I put the car into drive, it accelerates on its own to about 30 - 40mph.

My car has 105000 miles.
My car has an automatic transmission.