Combine all the marinade ingredients in a blender. Coat the chicken in the marinade and marinate overnight or for at least 4 hours.
Preheat the oven to 400°F
Remove the chicken from the marinade, discard marinade and season chicken with salt and pepper. Roast on a baking sheet until cooked through, about 22-25 minutes.
Toss the squash on a baking sheet (or two if you need more room) with the olive oil and salt. Roast for 20 minutes, or until beginning to brown. Toss with sage and pumpkin seeds.
Add all of the relish ingredients to a blender and blend until a few chunks remain.
To serve, divide roast chicken and squash between plates. Top with relish.