Preheat oven to 180°C Brush a baking tray with oil to lightly grease. Line with non-stick baking paper.
Place the beer and sugar in a medium saucepan over low heat and cook, stirring, for 5 minutes or until the sugar dissolves. Add the peanuts and simmer, stirring occasionally, for 15 minutes or until the liquid is absorbed. Remove from heat and stir in the chilli powder and salt.
Spread the peanut mixture over the prepared tray. Bake in oven, stirring every 5 minutes, for 15 minutes or until crisp. Set aside to cool completely. Break into pieces to serve.