We see, what a handful of fighters and a half dozen palace security guards?Naboo's standing forces were a big enough organization to have both an air force and organized ground troops.
If you want to call that an 'army' I guess I can't stop you, but it's not how I would use the term. But sure, if you define an army as a handful of fighters and a half dozen palace security guards, then Naboo had an army.
They have an army like the Vatican has an army.
They succeeded because Anakin did wacky plot hijinks and blew up the control ship. The starfighters did very little.They had their own custom designed and built starfighters that were kept on call. With enough fighters to take on the Trade Federation fleet in space and succeed.
They didn't hold their own, though--they lost against them. The droids rounded them all and then they surrendered.I think we see at least a dozen fighters in the movie, and they had enough that they could afford to let one go missing without it being a problem. On the ground, the Trade Federation had at least a dozen tanks and a dozen troop carriers that probably held about a thousand battle droids each. The Gungan's weren't winning against them, but they also weren't overwhelmed. They had nearly matching manpower and enough firepower available on instant call to hold their own against them.
Then the droids all shut down because of Anakin's aforementioned wacky plot hijinks. Otherwise the Gungans would have been toast.

