Treat Chives and Lettuce as uncertain neighbors because extension sources conflict. Extension-source claims conflict for this pair, so PlantNeighbors does not mark it as a companion or an incompatible pairing.
Because the compiled extension sources do not point in one direction, this page keeps the pair neutral. Use ordinary spacing, match the crops by light and water needs, and avoid treating the pair as either a proven companion or a proven problem.
Source basis: Virginia Cooperative Extension companion planting chart.
Spacing tip: Use the normal spacing for the larger crop, then tuck the smaller crop where it will still get light and water.