2tablespoonsplain yogurtcontaining live active cultures
Make sure the Instant Pot insert is clean and free of residue.
Pour about half of the milk into the Instant Pot insert. Add the sweetened condensed milk and whisk until combined. You can tell it is combined well enough when you tilt the pot and don't see any sweetened condensed milk on the bottom of the pot. Pour in the remaining milk and whisk to combine. Whisk in the yogurt, until smooth.
Place pot insert into the Instant Pot, if it isn't already, and cover with a glass or silicone lid or plate. Does not need to seal. Press the yogurt button and verify it is set on normal pressure for 8 hours. Instant Pot will count up to the 8-hour mark, then beep and display "YOGT" when it is done.
When done, remove the lid and remove the insert pot. Cover pot and refrigerate overnight, or for at least 4-6 hours. Do not stir yogurt until it is fully chilled.
Store Instant Pot yogurt in an airtight container in the refrigerator for up to 2-3 weeks.