In most cases there is need for stretching. However, you cannot assume that the lower two voices (basso, tenor) and the two upper voices (alto, soprano) are always to be played with the left or right hand. This applies not only to the chorales but to any polyphonic piece, especially fugues, where you will also have to deal with voice crossing and find a way to distribute the voices over the hands and fingers.
For example, in the first measure (A major chord), you play the lower basso voice with the LH and the other three voices (C# E A) with the RH. So, in this case the tenor voice needs to be played with the RH. Same reasoning applies to the rest of the piece. I suggest you draw a line in the score separating the voices per hand or colour the problematic voices. See example below.