Turn the Instant Pot to saute mode. Put 1 1/2 cups of water inside the Instant Pot. Put a glass bowl inside that fits as well. This is going to be your double broiler.
Put the candy melts into the bowl and stir until melted.
Grab the silicone molds and grease them. Once done add in the chocolate to coat the molds completely. Pop in the freezer when you're done for about 5 minutes. Once the time has passed, take out the molds and put in 1/2 teaspoon of your cocoa powder and marshmallows in each mold.
Put a bit more of the melted chocolate on top of the marshmallows to close the mold. Put back in the freezer for about 10 minutes.
Take out of the freezer and get the cocoa bombs out of the mold by pushing on the sides of the mold until they come out.
Using a different bowl, melt almond bark and about 2 ounces of the candy melts in the Instant Pot again, the same as before.
Grab a wooden spoon and drizzle the melted mixture over the bombs.
Put the Lucky Charms marshmallows on top asap.