2001 Chevy Tahoe ac belt broke is it difficult to replace?

I believe you have a serp belt (one belt runs everything). It isn't hard to replace, just follow the belt routing diagram under the hood. If you can't find it, let me know.

the ac has its own belt and tensioner. you can access from the bottom

It is an easy one. Here is the belt routing diagram for it. Turn the adjuster to loosten the belt and then replace it. THe adjuster pivots. Take a look at this and let me know if it is the correct one and if it helps:

https://www.2carpros.com/car_repair_information/year/2001/make/chevrolet/model/tahoe/2001_chevrolet_tahoe_drive_belt_routing_diagram.htm