In a saucepan, heat 1 tablespoon olive oil over medium heat. Add half of the garlic and the couscous and cook, stirring, for 3 minutes. Add the vegetable broth; bring to a boil. Cover, lower the heat and simmer until the broth has been absorbed, about 10 minutes. Stir in the raisins; season with salt.
Meanwhile, in a skillet, heat the remaining 1 tablespoon olive oil over medium heat. Add the remaining garlic and the swiss chard stems and cook, stirring occasionally, for 5 minutes. Add the swiss chard leaves, chickpeas and 1/2 cup water, cover and cook, turning, until the chard is wilted, 2 to 3 minutes; season with salt and pepper. Serve on the couscous and top with the feta.