Turn on a multi-functional pressure cooker (such as Instant Pot®), add olive oil, and select Saute function. Add ground venison and pepper; cook and stir until browned and crumbly, 5 to 7 minutes. Add tomato sauce, diced tomatoes, chili beans, kidney beans, and black beans; stir to combine.
Mix in onion and garlic, and then add cocoa powder, marjoram, chili powder, parsley, red pepper flakes, and bay leaves. Stir until well combined and cancel Saute function.
Close and lock the lid. Select 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. Remove bay leaves before serving.