Yes for most airbrushes you can buy different needle and nozzle sizes. But you always have to change the needle and the nozzle to the same size.
Most manufactures have a package of needle and nozzle for sale.
You need to be more specific, what airbrush do you want to change?, is it a solo or a 2 in 1?, I personally don't believe that this is possible with every model, as well as the fact that the needle needs to match the nozzle, the shaft of the needle would also need to be the same thickness, otherwise it might be necessary to also change the teflon seals or O-rings.
I would check first with the manufacturer of your airbrush before risking irreparable damage.