Press your tofu for 15-20 minutes, either using a tofu press or by wrapping the block of tofu in a towel/paper towel and placing a heavy object on top (such as a cast iron pan). Then, cut the tofu into about 1inch cubes.
Add the tofu to a large bowl along with the cornstarch, half of the olive oil, and salt & pepper. Gently toss with your hands (or tongs) until fully coated.
Spread tofu out onto the Ninja Combi air fryer tray, leaving room for the brussels sprouts. Then, add brussels sprouts and toss with the remaining olive oil and salt + pepper. It'll be tight to fit everything on there, but it'll work!
Place the tray with the tofu & brussels sprouts into Level 1 of your Ninja Combi. Then, add rinsed rice and water to the Combi Pan and place it into Level 2 of your Ninja Combi.
Set it to the "Combi Meals" function with the temperature at 350F for 15 minutes. If you want maximum crispiness on all sides of the tofu, feel free to flip everything at the halfway point - I usually don't because I'm lazy lol!
While that is cooking, add balsamic, coconut aminos, garlic, dijon, maple syrup/honey and salt & pepper to a small pot and whisk together. Bring it to a gentle boil over medium heat. Once boiling, reduce the heat to medium low and continue cooking, stirring occasionally, until the balsamic is thick and reduced (about 15-20 minutes).
Toss the cooked tofu and brussels sprouts with the reduced balsamic sauce. Serve over the white rice and top with chopped green onion, if desired!