i don't know, but must thought about it, 

it depends on the kind of ester you have....methyl esters hardly would be affected by cat. hydrogenation which would reduce your nitrile...in case of benzylesters this would give in turn the corresponding aldehyde....

Catalytic hydrogenation; good selectivity for nitriles can be achieved with Raney Cobalt. See Org. Biomol. Chem., 2014, 12, 7433 for a recent review on that reagent.

Borane in refluxing THF should work too.

You can kindly go through the patent   where you will find selective reduction of nitrile in presence of ester/ or you can try with Raney nickel in methanol ammonia (10-12% ammonia) solution under 65-70 psi Hydrogen pressure.

Hello, Cata. H2 should do the trick. 

Have a look at:

http://chemistry.mdma.ch/hiveboard/methods/000353051.html 

Aromatic nitriles: soft condition catalytic hydrogenation (Pd/C). Very simply operationally: transfer hydrogenation.   

 Aliphatic nitriles: harder conditions to drive forward reduction. Medium pressure hydrogenation (catalysts Pd, Pt, Co, Ni).