Google might bring back "Night mode" to Nexus Smartphones. The feature was removed earlier after Android 7.0.1 beta update. According to Ian Lake from Google: "Night mode requires driver support that is no present on Nexus devices".
But it seems that Google must have heard Angry Nexus users (As They want the Night mode back) because today someone at Google has marked the issue as "closed" with a status of "FutureRelease".
Google might include the "Night mode" feature in future Beta update for Nexus 6P and 5X.