Broncos led from the start, with Michael Robertson diving over in the second minute to establish an early 6-0 lead.
The Broncos then added three more scores including a stunning pitch-length break from Kieran Dixon to set up a 24-0 lead after 29 minutes.
Dixon again struck early in the second half to extend the Broncos' lead, shortly followed by a second try for Robinson.
In spite of having Michael Dobson sent to the sin bin, Hull responded with two tries from Chris Heil and Con Mika to set the score at 36-24.
The Broncos looked to have secured victory as Olsi Krasniqi went over in the 68th minute but late Hull tries from Ben Galea and Dobson ensured a tense ending.
Luke Dorn and Con Mika exchanged further late scores, as the Broncos held out to secure a 48-42 thriller.