A second break at 5-3 secured the first set but it was tougher for Djokovic in the second set.
He saved two break points in the first game, another at 2-2, with some solid serving and a wrong-footing forehand.
Nadal ended last season in October to overcome a niggling wrist problem but, after proving his fitness in a five-set thriller with Alexander Zverev, he has now shown his form against the tricky Monfils.
He has steadily played himself into form, and will feel a growing confidence when he begins his campaign in SW19 against Slovakia's Martin Klizan on Tuesday.
With Andre Agassi already on his coaching team for the coming fortnight, Djokovic has made a second addition to his ranks by bringing in the former Wimbledon semi-finalist Mario Ancic as extra support.
Djokovic wrapped up the 68th title of his career with another break in the tenth game, when Monfils overhit his booming forehand.
Novak Djokovic landed his first title since January as he triumphed at the Aegon International in Eastbourne.
There was plenty of crowd-pleasing big-hitting from the entertaining but erratic Monfils, which forced Djokovic into some trademark stoic defence on the baseline.