Computing redemption miles on *G using NH miles
 

I have a bunch of miles accumulated on NH am trying to redeem for *G award going IAD-BOM in Y. The NH web tool and rules they provide are extremely confusing. The issue I think also has to do with the stopover in Europe - depending on whether I get seats via FRA or ZRH or VIE. Can anyone let me know how many miles I will need - 65k or 75k? Thanks.

It's really not that confusing if you think about it in simple terms.

The distance of IAD-ZRH-BOM is 8225 miles one-way, 16450 miles return.

Looking at the required miles chart, when the roundtrip number of miles is between 14,001 to 18,000, the required number of miles in Y is 65,000.

The required number of miles will not change whether you change at ZRH, VIE or FRA.

ANA redemptions are pretty flexible and straightforward.
As stargold indicates, distance traveled by each segment counts.
ANA awards can be good values for shorter trips with multiple stopovers; they are less attractive for longer trips (e.g., NH is attractive for Europe trips from the East coast of the US, but less attractive from the West coast), but you can do your own calculations.
On a side note, don't forget that LX is also available for NH awards, but you have to call to redeem on LX.