On the toilet bowl the nuts spin on the bolts. I know plumbers use
A Jonnii-Bar to hold the bolt while you take off the nut. Is there a similar
Tool you can use, maybe like a vise-grip?
Toilet leaks around toilet base. Needs new wax ring

If you have not already done so, loosen or remove the bolt on the other side. Then lift or tilt up the toilet on the side of the turning bolt. Toilet bolts have an elongated head that is engaged in the flange to keep it from turning. When the nut is loosened the head of the bolt can drop down and turn. Holding the bolt up (by lifting the toilet) will prevent it from turning.

Thank you very good

Pastor,
Try using plastic closet bolts when you reinstall the toilet; they are very strong, they won't rust, they are easy to cut if needed, they will break if over tightened so there is no risk of damaging the bowl, and, they have a square shoulder that locks the bolt in the flange, this prevents the bolt from turning as you tighten or loosen the nut...

Very good thanks for the tip

Wish I had known this, speaking as a 68 year old woman with a sore back, who recently installed a HEAVY one piece toilet on spinning brass bolts.... plus I put the wax ring on the toilet first, instead of the flange, so it smooshed across the floor when I slid the toilet just a few inches.

Somehow I got it on and it didn't leak. KNOCK ON WOOD!