Hello everyone!
This guide may seem a little weird, but I've played a lot of Adc Nami myself and it worked out fine for me.
Why Nami adc? Well you have a range of 550 which is good if you're gonna play as an adc, you have decent mobility, you have a whole lot of CC, and your W gives you a little more sustain early game.
Why not just go AP Nami? Well the answer is easy: AP Nami is **** because you scale realy bad. With Nami adc you get te same cc, but a lot more damage in comparison. You heal some less, but hey, beggers can't be choosers.

I hope you guys will enjoy this guide and have fun playing adc Nami!

Try to rush Infinity Edge, when losing lane hard you might want to go for Static Shiv for the extra waveclear it gives.

Even when your ahead earlygame buy a Static Shiv and not a Phantom Dancer, because you need it for the extra waveclear.

If you buy Triforce use it well. For example you can use your E, proc it once, then lock someon e down with your Q, and while he is stunned use your W to proc it again.

Just use your standard Adc runes and masteries, or if you want to spam a lot maybe with a little extra mana regeneration.

When you try to lock someone down, use your E to slow them, after that use your Q while he is slowed so you can easily hit him with it. You can also use your ult after your Q so the enemy will be locked down even longer.
Also when getting chased, use your E to kite and when they get too close use your Q to stun them.

When you have trouble with farming (for example under tower) just use your E for farm, it makes it a lot easier. Nami's overall waveclear isnt very good. Using your Q on the caster minions can help a lot while pushing.

One important thing to remember: You are the ADC, so you will get focused. Try to stay safe and get in a good position for your ult. If you have a Bruiser like Jax in your team, dont forget you can also use your E on him, to give him extra movement speed to engage, a slow on his auto's and a little more damage.

Ofcourse playing nami as ADC has its benefits, but also its disadvantages.

Pros:

• Has good CC (Q: Stun E: Slow R: Knock-up)
• Can give a Movement Speed boost
• Good in teamfights
• Can kite easy

Cons:

• Has no scaling AD skills
• Waveclear is a little slow