with the same tools you can nourish on 4.
card by card comparisson:
overgrowth ramps 2 mana for 4 mana worth of tempo
nourish ramps 2 mana for 3 mana worth of tempo
pros of overgrowth: can be played 1 turn earlier
pros of nourish: effectively 1 mana cheaper than overgrowth tempo wise, can be tutored, can draw instead (or alongside with jerry)
i’d say overall the pros of nourish far outweight the pros of overgrowth.