So I really enjoy those bottled premade simmer sauces ("just add chicken!" - indian and thai ones in particular). For really tender chicken it takes about an hour of slow cooking, can you use store bought sauces in the pressure cooker? I don't know a think about cookers, apologies if it's a dumb question
If it only takes an hour in a regular cooker I don't see much benefit in using a pressure cooker. It won't save that much time, which is the main point of a pressure cooker.
The increased pressure in a pressure cooker speeds up cooking time. But first you have to let it build up the heat and pressure. I've used one often and find if you try to build that pressure too fast, with higher heat of course, you may run the risk of burning the food on the bottom of the cooker.
The pressure is created by the steam from water in the food/cooker. If those sauces are already thick it may create a problem: Not enough water etc to create adequate steam or end up with too thick (or a burnt) sauce.
A pressure cooker by it's very nature will 'leak' water/moisture out of the cooker via the valve at top. This is maintain or limit the pressure build up. So, if you're hell bent on trying it you may need to add a little water.
Fern