Until we have a full schematic of the device the OP is dealing with, we can't say anything about a few nA leak being "small" or not. No need to try and be smartasses - yes, one can measure pA currents with specialized equipment, but yes, 1 nA is very "small" in practice, unless dealing with very specific designs and applications. But from the - very - succinct descrption of the OP, there is almost no reason to think that a few nA would be abnormal.
As already said above, typical silicon diodes will leak in the order of a couple tens of nA, with only a selected few that can get you lower than this, and not speaking of Schottky, for which it's usually in the µA range and higher.
Tantalum and electrolytic capacitors also leak significantly.
And since we can infer from what the OP says that the "leaky" part is around the power supplies of the device, then, uh. yeah.