Yeah there is. Groesbeek is very nice (although you'll have to climb a few hills on your bike), Beek-ubbergen is also beautifull. You can cycle through the forests around Nijmegen, you can also go to Goesbeek through the forests. Perhaps go cycling through the Betuwe, or around the Waal. There are actually a number of cycling routes around Nijmegen: http://www.mapmyride.com/nl/nijmegen-gelderland/