Preheat oven to 450° Fahrenheit. Evenly space two racks in the oven. Line one large baking sheet and one smaller baking sheet with parchment paper and set aside.
Prepare all the ingredients. Rinse the chickpeas in a colander and pat dry. Place the chickpeas in a food processor and pulse a few times until coarsely chopped. You want some good texture here, so don’t overdo it.
Cut the halved head of cabbage in half again, cutting through the core. Remove the core by cutting it out at an angle (see photos in post above). Shred the cabbage into thin slices using a sharp knife.
Quarter the red onion and remove the outer layer of skin. Slice each quarter into thin slices.
Remove the center stems from the Swiss chard leaves. Rinse the leaves to remove any dirt, then roughly chop into bite-sized pieces.
If you have a small mortar and pestle, give the fennel seeds a quick grind. It’ll help them add more flavor to the dish. If you don’t, don’t worry about it. They’ll still be delicious left whole.
In a medium bowl, combine the pulsed chickpeas with 2 tablespoons avocado oil, onion powder, garlic powder, ½ teaspoon salt, and ¼ teaspoon pepper. Stir to combine and evenly coat the chickpeas. Spread the chickpea mixture into an even layer on the smaller baking sheet, Place on the lower rack of the oven. Roast for 25-30 minutes, stirring every 10 minutes, until golden and crunchy.
In a large bowl, combine the shredded cabbage, red onion, 2 tablespoons avocado oil, fennel seeds, ½ teaspoon salt, and ¼ teaspoon pepper. Stir to evenly coat the cabbage. Spread the cabbage mixture into an even layer on the larger baking sheet. Place on the upper rack in the oven and roast for 20 minutes.
Add the Swiss chard leaves to the same large bowl used for the cabbage. Drizzle with a bit of oil and stir to coat the leaves evenly and pick up any remaining seasoning from the cabbage.
Add the Swiss chard to the large baking sheet and carefully toss with the cabbage mixture. Roast for 10-15 minutes, until the Swiss chard is wilted and the cabbage is beginning to carmelize around the edges.
While the vegetables are roasting, make the vinaigrette. Combine the orange juice, olive oil, vinegar, Dijon mustard, garlic powder, salt, and pepper in a small jar. Secure the lid and shake to combine.
Once the chickpeas and greens are done, remove from the oven and let cool for a couple of minutes before transferring them to a large bowl. Add the pepitas and drizzle with the vinaigrette. Toss and adjust seasoning, as desired. Serve warm or at room temperature.
Store any leftovers in the fridge for 2-3 days. The chickpeas will lose some of their crispiness in the fridge but overall the salad holds up fairly well. Serve leftover salad either cold or let it come to room temperature.