The defender and attacking midfielder will be heading to Victoria as part of the transformation under way at the red and whites
According to The Herald Sun, defender Chapman, 19, has been granted a release of his contract to move south after making six appearances for the Jets last term, down on the 17 matches he featured in during the 2012-13 campaign.
Attacking midfielder Brown, 24, started only three matches last season, and has struggled to build on the early promise he showed when he debuted in the competition with Gold Coast United.
Brown, who reportedly sought to leave Hunter Stadium in the mid-season transfer window, was out of contract.
Heart are also understood to have secured the services of midfielder Aaron Mooy from Western Sydney Wanderers.
Under new owners in the form of Premier League giants Manchester City, and with John van 't Schip back at the helm as coach, Heart are embarking on a significant overhaul to their squad, with international and domestic marquee positions yet to be filled and room for two more non-marquee overseas players.