It would be Neat or Kudos for me.
Agree with Ponty, as above.
But you have an embarrassment of riches when it comes to speaker choice for an SN. My personal experience is with SN1 and SN2, as well as Nait XS2.
Neat and Kudos have great synergy with those Naim integrateds; I loved an earlier Kudos Cardea 1, and have kept my Neat Momentum SX3i. If you might consider used speakers, the now discontinued SX3i would be a great buy and a great match.
Other offerings from PMC and Proac would be fine if their sound signature is to your taste, likewise, for the BBC influenced Spendor Classic line, Graham LS5/9 and Harbeth Monitor 30.1, for example - I only mention these because I have heard great things with these models, paired with the SN2 and/or Nait SX2.
Kudos, Neat, Proac; more verve, compared to BBC style. A matter of taste, and musical choice…
Other posters have named entirely different speaker lines that I’ve never personally heard, but have heard good things about, such as Fyne and Living Voice; would love to hear those with an SN3 - no reason to doubt a good partnership.
Hard to go wrong, unless the speakers you choose are otherwise unsuitable to your room, or musical taste, or have exceptionally high power requirements…