Calvin Harrison made a First-Class top score of 52, and took three important wickets, while Lyndon James scored 96 to put Notts into a solid position by the close of play on day two.
The pair shared a seventh wicket stand worth 146 to take the Green and Golds beyond a third batting point and to an ultimate first innings total of 399.
Luke Fletcher and Dillon Pennington then claimed early scalps - the latter's first pouched wonderfully by Harrison at slip - before the leg-spinner took his trio to leave Worcestershire trailing by 179 with four wickets remaining at stumps.