One Pot Mexican Gnocchi

• 800 g tin diced tomatoes
• 400 g tin lentils, drained
• 400 g tin black beans, drained
• 400 g tin corn kernels, drained
• 2 tbsp mexican spice
• 200 g tomatoes, diced
• 0.25 red onion, finely chopped
• 1 cup fresh coriander, chopped
• 1 lime
• 500 g dry gnocchi
• 0.5 cup shredded cheese
• 1 avocado, thinly sliced