Since canned asparagus is already cooked, you don't need to pressure cook it unless you're adding it to another recipe like a soup. You are better off air frying it for a few minutes to crisp and warm it up, like I do with air fried green beans. You can use frozen, raw asparagus in the Instant Pot. Add 1 minute of cook time for frozen. Take note of how thick the asparagus spears are, as if they are very thin you should be fine cooking them for the same time that you would cook thawed, raw asparagus.