The 19-year-old Royals forward, who enjoyed loan spells at Northampton and Cheltenham last season, marked his County debut with a goal in Tuesday's 4-1 win at Crewe in the Johnstone's Paint Trophy.
Playmaker Carl Baker scored a hat-trick at Gresty Road, but Bignall's impact has left Ablett equally encouraged.
Ablett said: "Carl is in a rich vein of form at the moment but Nicholas has made a big impact up front.
"He has pace and power and that is why we brought him in."
Source: Team_Talk