It seems Galaxy Note 4 owners in the US are set to receive the Android 5.0 Lollipop update on all the major carriers this month. Soon after T-Mobile started updating the device to Lollipop, Sprint has started doing the same.
It's unclear if the update has started rolling out yet, but Sprint's support page says the rollout is slated to begin today, with the update carrying build number N910PVPU1BOB7. Like the T-Mobile variant, Sprint's version of the Note 4 will get the usual features of Lollipop and also receive Wi-Fi calling enhancements.
Keep an eye out for the notification for the update on your Galaxy Note 4; you can see if the update is available right now by going into the Settings » About phone » Software updates menu and hitting the Check now button.