Top scorer Deeney comes back into the fold having served a two-match ban for his dismissal against Stockport, missing the back-to-back 2-1 home victories over Wycombe and Tranmere.
But Nicholls, who led the attack alongside matchwinner Darren Byfield on Saturday, sustained a calf strain and will be assessed.
Right-back Rhys Weston missed out against Rovers at the weekend having picked up a hamstring problem in training on Friday and will again miss out.
The Saddlers have enjoyed a turn in fortunes of late and are now unbeaten in three after experiencing a dip in form.
And manager Chris Hutchings will be hoping his mid-table side can continue their run over the remaining five matches to improve on their 12th and 13th place finishes from the past two campaigns.