The CH(2Π)+N2 reaction over the ground state potential energy surface has been investigated at the G2M level of theory. This reaction is directly relevant to hydrocarbon combustion chemistry, in particular, to 'prompt NO' formation. A detailed mechanism via stepwise and concerted pathways to form HNCN, involving chain and cyclic intermediates, is presented. The proposed mechanism for NO formation is more favorable than the commonly assumed spin-forbidden path producing HCN+N(4S). The theoretically predicted heats of formation for NCN and HNCN are in excellent agreement with the recently reported experimental values.