Alternative to Merge tables

You can also use Table.Join instead of Table.NestedJoin. Just make sure that you remove the "NewColumnName" parameter, and change "Table.NestedJoin" to "Table.Join". You might also want to make the key column distinct using Remove Duplicates. Even if there are no duplicates, this tells M that there are no duplicates. Table.Join is faster in my experience than the NestedJoin (for sure when you consider the time taken to expand the tables), especially with inner joins, and if your key and the other table's columns are both sorted ascending, then you can add the JoinAlgorithm.SortMerge parameter to the Table.Join function, and you will see your query finish processing in seconds. The NestedJoin function doesn't allow that parameter. And as if all that weren't enough, if you use an inner join with Table.Join, your key and foreign columns can have the exact same name, and Power Query will leave you with just one resulting key column--no need to rename anything.

Go forth and merge some stuff!

--Nate