Nested IFs Workaround
I've seen a few different ways. Here is something I saw by Aladin Akyurek.
Assuming the Item to be found is in A1. ("aa" should be matched with "ba", etc)
In cell C1 enter
=VLOOKUP(A1,{"aa","ba";"ab","bb";"ac","bc";"ad","bd";"ae","be";"af","bf";"ag","bg";"ah","bh";"ai","bi";"aj","bj"},2,0)
then in cell B1 enter
=IF(ISNA(C1),"",C1)
or you could nest both formulas like this
=IF(ISNA(VLOOKUP(A1,{"aa","ba";"ab","bb";"ac","bc";"ad","bd";"ae","be";"af","bf";"ag","bg";"ah","bh";"ai","bi";"aj","bj"},2,0)),"",VLOOKUP(A1,"aa","ba";"ab","bb";"ac","bc";"ad","bd";"ae","be";"af","bf";"ag","bg";"ah","bh";"ai","bi";"aj","bj"},2,0))