Turn on a multi-functional pressure cooker (such as Instant Pot(R)) and select Saute function. Add bacon; cook until crispy, 8 to 10 minutes. Pull bacon out with tongs and set in a bowl. Add kielbasa to the pot; lightly brown on all sides, 5 to 7 minutes. Remove with tongs and place in the bowl with the bacon.
Saute onions in the pot until soft, 2 to 3 minutes. Crumble the bacon and add to the pot. Stir in brown sugar. Add potatoes, sauerkraut, chicken broth, apple, beer, and salt. Mix gently.
Close and lock the lid. Select high pressure according to manufacturer's instructions; set timer for 12 minutes. Allow 10 to 15 minutes for pressure to build.
Release pressure using the natural-release method for 10 minutes according to manufacturer's instructions. Release remaining pressure carefully using the quick-release method. Unlock and remove the lid.
If you'd like to substitute liquid smoke for the bacon, melt 3 tablespoons butter in the pot before adding kielbasa. Stir in 3 drops liquid smoke before adding the broth. I suggest adding the drops to a teaspoon to avoid accidental overuse of smoke.