Preheat the oven to 375℉. Mix together the biscuits according to the box instructions and sat to the side.
Then, chop up the shredded chicken into small chunks. In a pot on medium heat, sauté the onions. Once they are soft and browning, add in the butter. Now, toss in the flour then cook the flour with the onions for a minute. Slowly, whisk in the milk and the broth next.
Once added and the sauce is starting to thicken, add in the seasoning, mixed veggies and chopped chicken. Then, turn off the heat, everything should be thick and creamy.
Pour the filling into the baking dish.
Make the biscuit mix and add the extra seasonings into the dough. Then, take dollops of the biscuit mix and spread it across the dish. It doesn't have to be perfect, it'll spread.
Place in the oven for 20 minutes then turn on the broil to brown the biscuit tops a little more. Remove from oven then brush the topping with the butter and seasoning packet from the biscuit box.