auto fill text cell based on text of another

Hello,

Is there a way to automatically fill each cell of column1A of sheet1 based on the text on column1B cells of the same sheet1 according to the equivalent pair of cells from another sheet2?

To elaborate:

I have a list on sheet2 containing unique names on col2A and their correspondent unique text codes on col2B.

I have another working sheet1 with an empty col1A and a filled col1B containing text codeson random order. I want to fill col1A automatically with the names that correspond to the text codes next to them.

Example: I have "qwertyu" typed on several randomly located cells in col1B.

On the sheet2 list "qwertyu" on col2B corresponds to "Jonh" on col2A.

I want the program to find "qwertyu" code on the list, and type its corresponent name "Jonh" on each col1A cell that is next to a col1B cell containing "qwertyu". I don't want order of sheet1 lines changing.

Is this possible using excel?

Thank you in advance.

(Note that the list is not so short that I can simply add it on the =if(B="qwertyu","Jonh",(if....)) formula itself)