Tip
Nami has great sustainability due to her (W), so try to preserve your health with [E] while engaging. However, you can go in for the kill when Nami gets caught airborne with [Q] as Nami has low health.
Janna vs Nami

Nami has great sustainability due to her (W), so try to preserve your health with [E] while engaging. However, you can go in for the kill when Nami gets caught airborne with [Q] as Nami has low health.