First, cook the rice. Rinse the rice well. Boil the broth, add the rice, reduce heat to very low, cover tightly, and simmer for 45 minutes. Remove from heat and let sit 10 minutes. Check the rice and make sure it's cooked through.
Meanwhile, add the oil to a medium saucepan over medium heat, and add the onions (do NOT add salt). Saute for about 5 minutes and then add the mushrooms. Saute until you start to see color on the mushrooms, and then reduce the heat to medium-low and add the garlic and a little salt, being careful not to burn the garlic. Once the garlic is cooked through and mellowed (about 3-5 minutes), add the nuts. Stir and then turn the heat to low. Try to time this so it finishes when the rice is finished.
When the rice is finished cooking, take the top off and let the steam come off for just a couple of minutes. Then add the rice to the skillet with the mushroom mixture, and fold together gently until combined. Finish with some olive oil and salt & pepper.