1. Combine first 7 ingredients in a large bowl; pour milk over mixture, stirring to combine. Cover and chill 3 hours or overnight.
2. Combine nuts and pumpkinseed kernels in a small bowl. Spoon 3/4 cup oat mixture into each of 6 bowls. Top each serving with 1/2 cup yogurt; sprinkle each serving with 1 1/2 tablespoons nut mixture, and drizzle with 1 teaspoon maple syrup.