ISTM that the 2019 Leaf will be a direct competitor to the Bolt, at least on paper. They will have very similar performance, range, and price. Leaf gets an edge on charging though - the current Bolt only charges up to 55kW. 100kW DC charging would be very welcome.
Then there are the "other" factors which will result in a market for both. The Bolt will be the sportier-handling car, and the Leaf will be the softer family car.