Combine cumin, coriander, cardamom and salt in a bowl. Heat a heavy-based large frying pan over medium heat. Add spice mixture and cook, stirring, for 1 minute. Add 1 tbsp oil and chickpeas to the pan and cook, tossing often, for 4-5 minutes until just crispy on the outside. Transfer to a bowl.
Add 1 tbsp oil to the pan and heat over medium-high heat until hot. Add rainbow chard stems and cook, tossing often, for 2-3 minutes until softening. Add rainbow chard leaves and quickly toss until almost wilting. Remove from heat. Set aside to cool slightly.
Combine the yoghurt, lemon juice and garlic in a bowl. Season with salt and pepper. Mix until smooth.
Toss the rainbow chard and chickpeas into a large serving bowl. Toss through pine nuts. Drizzle with the yoghurt mixture.