You can put frozen food in a toaster oven.
Toaster ovens can cook frozen food or you can thaw the food out first before cooking.
Frozen foods can take longer to cook in the toaster oven than thawed foods although it's okay to cook the frozen food in the toaster oven.
For frozen meats, thawing the meats out before cooking them in the toaster oven can help the meats cook faster and more evenly.
But if you prefer to cook the meat from frozen in the toaster oven you can do so.
The toaster oven will thaw the meats and other foods as they cook.
When cooking pizza or pot pies in the toaster oven it's recommended that you cook the frozen pizza or frozen pot pies in the toaster oven without thawing them first.
However if you want to thaw the pizza or pot pies out before cooking them, you can do so as well.