In a bowl, coat the chicken breasts with 1 tbsp vegetable oil, 1 tbsp yaji, and 1 tbsp chicken bouillon. Mix well.
Heat a cast iron skillet over medium-high heat. Line with parchment paper if desired.
Cook the chicken on both sides until browned and cooked through. Remove and let rest.
While the chicken cooks, quarter the potatoes and add them to the same bowl used for the chicken.
Add the remaining yaji, chicken bouillon, and any leftover oil. Toss to coat.
Air fry the potatoes until golden and tender.
Slice the rested chicken and serve with the suya potatoes.
Optional: sprinkle extra yaji and chopped green onions before serving.