What’s the trick to not baking tough chicken in the oven?

Try brining it - just a simple salt water brine might help.

Are you talking about boneless skinless chicken breasts? If so, THIS is the technique and timing. Exclude the brown sugar in the seasonings called for or use your own seasonings. The keys are: Pound chicken, olive oil both sides, season both sides, 425 degrees, 16 minutes, broil for the last 2 minutes. Remove from oven, let rest for 5 minutes. It's PERFECT every time!

30-60 minutes in buttermilk is another way to break down some of the muscle and make it super tender. 

I have found that my chicken turns out better if I cut the time short and let it rest to finish cooking.

Definitely this, especially for a roast.

I brine chicken and pork (water, peppercorns, coriander seeds, bay leaf, and garlic).  Comes out juicy every time.  

I never brine.

I bake my thinner breasts at 375° for 25 min then check internal temp. Sometimes I need to go to 30 min.

Larger while breasts at 400° for 35 to 40 min.

I pay dry, add olive oil and season.

I always rest my chicken 10 min before cutting.

You can always try braising your meat. It's done on the stove top and produces awesome meals.

I dry-brine my chicken. About two hours to an hour before cooking, I trim and dry my chicken with a paper towel, then salt it on both sides (usually with kosher salt) and put it in the refrigerator on a rack over a sheet pan. It will first draw out the moisture and then draw it back in and help tenderize the meat. Then, when I cook it, whether in the oven or on the stove, I make sure to temp it and not let it go above 155-157 degrees. After cooking, tent it with aluminum foil (just place the foil over whatever plate you've put it on to keep in the heat and moisture) and let it rest for 5-10 minutes. It will continue to cook as it rests and come up to 165 and that way it won't overcook and get dry. 

Jen

Chicken and pork bake up wonderfully tender in the oven if you leave the skin on. Otherwise all the moisture escapes. Time depends on weight and thickness.

If the pieces don’t have skin, cover them with something else. My ddil cooked up some wonderfully tender juicy skinless chicken breasts last week, covering them with mayonnaise and spices.

Sorry, this doesn't answer your question but my secret is to use my AF.

In the oven, then you need to follow the above advice. I will say brining is a huge boost. My DD does a spatchcock chicken during the year and does a spatchcock turkey at Thanksgiving. She does a dry brine for 24 hours on each. For the during the year chicken, it just takes planning. It is fabulous every time!

Ina Garten uses boneless with skin on (hard to find) and puts butter or oil under the skin.