Preheat the oven to 450F or 425F convection. Line a baking sheet with parchment paper. Add the chicken, radish, and broccoli. Drizzle with the olive oil and sprinkle with oregano, salt, and pepper. Use your hands to toss everything together to coat in the oil and spices. Spread into an even layer and bake for 20 minutes, or until the broccoli is slightly charred and radishes are browned on the bottom.
In a high-speed blender, add the artichokes, herbs, water, oil, tahini, lemon juice, mustard, salt, and garlic (if using) and blend on low, slowly increasing to high until totally smooth.
Add about ¾ cup of warm grains to your bowl and top with the chicken/veggies, artichoke sauce, nuts, and herbs. Squeeze lemon generously all over. Sprinkle with some salt and pepper.