Heat a large skillet over medium heat. Add the chorizo and onion and cook, stirring often, until the onion is soft and the chorizo is fully cooked, 5 to 6 minutes. Transfer to paper towels to drain the excess grease. Set aside to cool.
Combine the eggs, heavy cream, sour cream, salt and pepper in a large bowl. Whisk until light and fluffy, about 1 minute.
Generously coat the cups of a silicone egg bites mold (you can find them online!) with cooking spray. Divide the cheese among the cups. Divide the chorizo and onion among the cups. Then fill the cups with the egg mixture, leaving a little space at the top.
Multi-cooker directions: Set the trivet in a multi-cooker, then carefully pour 1 cup water into the pot. Cover the mold snugly with foil and carefully lower it onto the trivet.
Secure the lid on the multi-cooker and set the pressure valve to sealing. Press the steam button and set it to 10 minutes. (Note: It will take several minutes for the pressure to build, after which the 10-minute timer will automatically start counting down.)
After the 10 minutes are up, let the pressure release naturally for 10 minutes, then use the handle of a wooden spoon to move the valve to venting, which will let the rest of the pressure release quickly.
When the pressure is fully released, carefully remove the lid. Remove the silicone mold from the machine. Peel back the foil and turn the egg bites onto a plate. They should pop right out!
Standard oven directions: Preheat the oven to 325 degrees F. Pour water into a 9-by-13-inch baking dish until it's halfway full. Set the mold in the baking dish, then cover the baking dish with foil. Bake until the eggs are set, about 1 hour. Let the mold sit in the water for 10 minutes before removing the egg bites from the mold.
Freezing and reheating instructions: Freeze by placing the bites on a lightly greased sheet pan or plate and freeze for 45 minutes. Transfer to a plastic zipper bag and return to the freezer.
To reheat 1 or 2 bites, wrap in a paper towel and microwave for 1 minute. Let sit for 1 minute before eating.