Prepare rice according to package directions. Heat 1 tablespoon of oil in a large pan over medium heat. Add onions and cook 8 minutes, stirring occasionally, until softened. Stir in garlic, curry, and cumin. Cook for 1-2 minutes more.

Add the remaining oil and the chicken and cook for 10 minutes, stirring to coat chicken in spice mixture. Fold in lentils and cover and simmer until chicken is thoroughly cooked, about 5 minutes. Stir in yogurt. Serve over rice and garnish with cashews, if desired.