Cut the chicken into bite-size pieces and sprinkle with salt, pepper, curry, Garam Masala and sugar. Place it in a bowl or Ziploc bag.
Pour the yogurt over the chicken making sure to cover each piece. Set the chicken aside until ready to cook. If cooking within 10 minutes, it is fine to leave on the counter. If letting it rest more than 10 minutes, refrigerate until ready to cook.
If planning on freezing Chicken Tikka Masala, make double sauce and freeze half. Freeze it separately without the chicken. When ready to serve, prepare the chicken as directed, then add it to the thawed sauce to simmer for 15-20 minutes or serve with rotisserie chicken.
If in a hurry, rotisserie chicken can be substituted for skillet cooked chicken.