Preheat the grill.
Strip the kale leaves from the tough stems and discard the stems. Toss the leaves on a rimmed baking sheet with 2 tablespoons of the olive oil and 1/4 teaspoon salt, and spread them out in an even layer. Grill the greens, stirring once or twice until they turn a brighter green with bits of charred leaves, about 4 minutes. Stir in the walnuts and grill until the walnuts are fragrant but not burned, about 2 minutes. Set aside to cool.
Sprinkle both sides of the chops with 1/2 teaspoon salt, 1/4 teaspoon pepper and the rosemary. Heat 2 tablespoons of the olive oil in a large skillet over medium heat and cook, turning once, until an instant-read thermometer inserted into the thickest part registers 62°C, about 12 minutes. Transfer to a cutting board to rest for 5 minutes.
While the chops are cooking, pulse the garlic and the cooled kale and walnuts in a food processor until chopped. Add the pepper flakes, lemon juice, 1/4 teaspoon salt and the remaining 1/2 cup olive oil and continue to process to make a slightly chunky pesto. Adjust the consistency as desired with up to 1/4 cup water. Season to taste with salt and pepper. Top each pork chop with about 2 tablespoons of the pesto and serve with a baked potato or soft polenta.