Rinse peas and toss with salt and pepper. Transfer to the bottom of a multi-functional pressure cooker (such as Instant Pot®); add chicken broth, tomatoes, ham, red onion, and garlic. Close and lock the lid.
Select Bean setting and high pressure according to manufacturer's instructions; set timer for 30 minutes. Allow 10 to 15 minutes for pressure to build.
Release pressure using the natural-release method according to manufacturer's instructions, 10 to 40 minutes.