Pre-heat your oven to 200 degrees Celsius (400 degrees F)
Put a sheet of baking paper over a board, enough to put all of your chicken breasts on.
Put the chicken breasts on the paper, making sure they are spaced out evenly. Then, place another sheet of baking paper on top of the chicken breasts.
Use a meat tenderiser (the flat side) or a wooden rolling pin to lightly bash the chicken breasts to flatten them out. Bash them to about an inch in thickness.
Season the chicken on both sides with salt and pepper and then pre-heat a large frying pan over high flame for about 1-2 minutes.
Add your oil, then gently add your chicken breasts. Cook the chicken for 3 minutes on each side.
Turn the heat off and then transfer the chicken onto a chopping board. Then dice the chicken into inch thick chunks.
Lay out your tortillas, place the diced chicken in the middle of tortilla in a linear form. Put a small amount of sauce over the chicken (making sure you have plenty left), then add your red onions and, 40-50% of your cheese and then add 1-2 sprigs of coriander on each tortilla.
Roll up the tortillas, by folding up the sides, and then roll up the tortillas through the middle. (if you don't understand this instruction, look at the video in the post)
Ladle and spread some more enchilada sauce on the bottom of a deep baking tray (making sure you have enough for the topping). Place your rolled up tortilla inside the tray neatly, spoon and spread the rest of your sauce on top of the tortillas evenly and finally, sprinkle the remaining of your cheese on top evenly.
Mix the black beans, cherry tomatoes and coriander together in a bowl. Then season with salt and pepper.
Store your enchiladas in 4 containers and then evenly add your salsa in each container. OR just serve them on a plate if you're not making these for meal prep.
Store away/serve and enjoy.