Place the kumara into a large saucepan and cover with water. Bring to a boil over high heat then reduce heat to medium-low, cover and simmer until tender (About 20 minutes). Drain and allow to steam dry for a minute or two. Mash kumara then set aside.
Sprinkle chicken tenders with steak seasoning; heat the oil in a large frying pan over medium heat and cook the chicken tenders until the meat is lightly browned and no longer pink inside (5 to 8 minutes per side). Remove the chicken and set aside. Stir the maple syrup into the frying pan, scraping up and dissolving any browned flavor bits from the frying pan. Bring to a boil, simmer for 2 minutes then stir in the spring onions.
To serve, place the mashed kumara onto a serving plate, top with the chicken tenders then pour the maple sauce over the chicken.