Adam Voges and Mark Wagh hit half centuries as Notts posted 251 all out on day two at Trent Bridge.
Their third wicket stand of 76 brought Notts back on track after the day-one dismissals of openers Will Jefferson and Matt Wood but West Indies seamer Corey Collymore had them both caught by Luke Wright.
Collymore struck again to dismiss Paul Franks, caught behind by Matt Prior after Samit Patel (26) and Chris Read (8) fell lbw.
Charlie Shreck and Darren Pattinson struck to dismiss openers Chris Nash and Carl Hopkinson to leave Sussex on 277 and 70-2 but Notts' position would have been stronger if Samit Patel had held Michael Yardy on five off Shreck.
Yardy stands on 31 not out overnight, much to the disappointment of Notts Director of Cricket Mick Newell.
“We have seen a couple of dropped catches which is always disappointing considering how well we have done in the slips but we’re hopeful that we can win the game if we manage to restrict them to between 250 and 275 in their second innings," said Newell.
“We are bowling as well as we have all season and I thought that we deserved more from today,”
“Mark Wagh and Adam Voges did relatively well and kept us in the hunt but I want to see our batsman go on to big scores once they have reached their 50.
“There’s a lot to do and we know that Sussex have players with international experience and it will be important for us to bowl well tomorrow.”
Mushtaq Ahmed claimed his first wicket of the season when he bowled Darren Pattinson and with Charlie Shreck for company, Graeme Swann’s aimless slog was caught by Jason Lewry to end the Notts innings.