Forest's Assombalonga was sorely missed last season
The Canaries will be looking to mount an immediate assault on promotion next season and are in need of attacking reinforcements following the return of last season's loan star Dieumerci Mbokani to Dynamo Kiev.
Mbokani scored seven goals on loan to Norwich
And one Congolese could be replaced by another in Assombalonga, who missed much of the 2015-16 campaign with a serious knee injury.
The latter, a £5.5 million capture from Peterborough United two summers ago, scored 15 goals in 29 Championship appearances for Forest before being sidelined.
Forest were 10th in the Championship when Assombalonga became sidelined
Forest tied Assombalonga to a five-year deal upon his arrival, however a lack of progress in their proposed takeover could prompt what would be an unwanted sale.
The Reds finished 16th in last season's Championship and are need of new additions with only two new faces arriving so far.
Norwich's finances were recently boosted by the £11 million sale of Nathan Redmond to Southampton.
Redmond's sale has boosted Norwich coffers