Make a few deep cuts through each chicken breast and place in a non-metallic dish. Place yoghurt, garam marsala, ginger, garlic, chillies, mint, coriander, turmeric, curry powder, lime juice and 1 teaspoon salt in a food processor. Whiz to combine.
Pour the mixture over the chicken breasts until they are well-coated and refrigerate overnight or for a minimum of 4 hours to marinate.
Meanwhile, to make the pineapple salsa, place the pineapple, onion, capsicums and coriander in a bowl and set aside.
Place vinegar, lime zest and juice, sugar and chillies in a small bowl. Stir to dissolve the sugar.
Add the dressing to the pineapple salsa, then stir to combine. Cover and set aside.
Preheat the oven to 240°C.
Remove the chicken breasts from the marinade; discard marinade. Place on a rack over a roasting tray and bake in the oven for 20-25 minutes or until cooked through and the outside is lightly charred.