For the chocolate nests: Melt the chocolate chips and the peanut butter on medium heat in a medium saucepan. Break the shredded wheat into little pieces, and mix into saucepan. Remove from heat and form into nests. Place on a plate, and freeze.
For the cupcakes: Preheat the oven to 350˚F. Line a muffin pan with paper liners.
In a large bowl, combine the flour, baking powder, salt and sugar. Add the oil, eggs, milk and vanilla extract with an electric mixer until fully combined.
Spoon the batter into the prepared muffin pans. Bake for around 25-30 minutes, or until a toothpick inserted comes out clean.
Cream together the buttercream ingredients with an electric mixer until smooth. Pipe onto cupcakes and place a chocolate egg on top.