ref – https://nodejs.org/en/docs/guides/event-loop-timers-and-nexttick/

process.nextTick() vs setImmediate()
We have two calls that are similar as far as users are concerned, but their names are confusing.

process.nextTick() fires immediately on the same phase

setImmediate() fires on the following iteration or ‘tick’ of the event loop

In essence, the names should be swapped. process.nextTick() fires more immediately than setImmediate(), but this is an artifact of the past which is unlikely to change. Making this switch would break a large percentage of the packages on npm. Every day more new modules are being added, which means every day we wait, more potential breakages occur. While they are confusing, the names themselves won’t change.

We recommend developers use setImmediate() in all cases because it’s easier to reason about.