Dice tomato and onion. Remove cilantro leaves and roughly chop.
Using the palm of your hand, roll lime back and forth on the counter top several times to help release the juice. Cut lime in half and squeeze juice into medium bowl.
Mix all ingredients together in a medium bowl.
Small dice onion, green bell pepper and red bell pepper. Measure all spices and place in a small bowl.
Measure beef broth using a liquid measuring cup. Add olive oil to a large sauté pan and heat over medium-high heat.
Add the onions and bell peppers and sauté until tender, about 5 minutes.
Add the ground beef and sauté while breaking up with the back of a wooden spoon. Cook until well browned and no pink showing, about 7-8 minutes.
Add remaining filling ingredients (spices & broth) and stir until well combined and some but not all of the liquid has been absorbed.
While meat mixture cooks, grate cheese and place in small bowl. Measure yogurt and place in small bowl. Make Pico de Gallo.
Place 2 taco shells on each plate.
Add ¼ cup beef mixture to each shell
Top each taco with 1 tablespoon yogurt, 1 tablespoon cheese and 1 tablespoon pico de gallo.