Not really familiar with this version of Sentry or his feats but if he has the Void in him, I don't see Immortal Hulk putting him down. Void is way, way beyond physical based characters like Hulk but I don't know how Void's power would translate or help Sentry to KO Hulk, not sure if this version of Hulk can even be KO'd by anybody less than a Skyfather level being.
This sentry stomps even using his own feats without void, he wrecked the avengers and no sold everything they had to offer. Hulk never took thors hits and got bloodied by she hulk and hurt by black panther. Also a much weaker sentry literally tore apart the hulkbuster suit just by blowing on it... the same hulkbuster that tanked a thunderclap from hulk and had to be physically torn by hulk.