in recognition of something
in requital of something
in reward for something
in a nod to something

She fell silent for a long moment, then her head moved in a slow nod.

The brown curls bobbed up and down in a nod.

He brought his chin forward in a nod that ended abruptly.

In a nod to conservatives, the Senate plan also includes several new tax breaks.

She moved her head in a subtle nod toward the counter.

Nicholas tipped his head toward the door in a single nod.

When they were silent, he jerked his head in a single short nod.

But his head moved in a nod, once, slightly up and down.

He moved his head up and down in a nod.

He dipped his head in what was closer to a bow than- a nod.