Not really. Assuming you are comparing an equal lens from each company (Say a 70-200/2.8 IS or VR II) then one *Might* be slightly better than the other (In the 70-200 the Canon is known to be better). The biggest difference isn't a "Better or Worse" thing (You can buy a $100 Nikon or Canon lens and a $10,000 Nikon or Canon lens) as much as it is which offers the best option for what you shoot. If money were no object, Canon's new IS II Super-Tele's (300/2.8 and 400/2.8 and 500/4 and 600/4) are all better than anything Nikon offers. Nikon doesn't offer a "VR" 300/4 like Canon. Nikon doesn't offer an affordable 400/5.6 like Canon. Nikon has a 80-400 VR but it is not nearly as good as Canon's 100-400 IS (Which itself is dated).
Most say Nikon's 14-24 is the best full-frame wide-angle lens available. Most say Canon's 85/1.2 and Tilt-shift lenses are in a class by themselves.
Canon is so much bigger / more widely used that the used market tends to be a huge advantage too. More lenses on the market tends to bring the prices down compared to Nikon. This is good and bad obviously (Good for selling / Bad for buying).
All that being said, I personally think Nikon's high-end Camera's are better (D800 Vs 5DIII for example) but that is a different discussion.
Jeff