A nozzle cap for a gas inlet fluidizing nozzle in the bottom plate of a post-combustion bed in a hot water or steam boiler with at least two fluidized beds is provided. Flue gases from an underlying combustion bed enter the post-combustion bed via a plurality of such gas inlet nozzles. Each nozzle cap is formed as a deflecting member for guiding the flue gases to the bed material and is shaped to minimize the risk of clogging of the cap with particles entrained in the flue gases and the risk of the cap being eroded by the fastly moving particles.