Nest if with INDEX, Match Function

I imagine I am closing this last argument out incorrectly which is why I am getting false on the last if statement no matter what it is. All the others before last if statement are working correctly, but below is an example of my problem with fake data.

For some reason, last keeps failing. If I pull it out and put it in a separate cell, it works correctly but failing as part of the complete if statement.

=IF(D7="bread","",
IF(D7="chicken","",
IF(D7="dog","",
IF(D7="bird","",
IF(D7="rat",INDEX('Sheet'!E:E,MATCH(A7,'Sheet2'!B:B),
IF(D7="mouse",INDEX('Sheet'!E:E,MATCH(A7,'Sheet2'!B:B),0),0)))))))