A turbine nozzle includes an airfoil that extends in span from an inner band to an outer band where the inner band and the outer band define inner and outer flow boundaries of the turbine nozzle. At least one of the inner band and the outer band define a first set of cooling channels and a second set of cooling channels formed beneath a gas side surface of the corresponding inner band or outer band. The inner band or the outer band further define a coolant distribution plenum that is in fluid communication with the first and second sets of cooling channels. The coolant distribution plenum provides a stream of coolant to at least one of the first set of cooling channels and the second set of cooling channels.