What is the verb for "pointing at something with one's chin"?

"Motioning (at)" includes "pointing at someone or something with one's head".

M-W:

motion verb
: to make a movement of your hand, head, etc., that tells someone to move or act in a certain way

She motioned to her assistant.
She motioned at the empty chair beside her and told me to sit down.

I prefer michael.hor257k 's answer, but another possibility would be to gesture

noun

1. a movement or position of the hand, arm, body, head, or face that is expressive of an idea, opinion, emotion, etc.

(Emphasis mine; quote from Dictionary.com.)

I’ve always understood “nodding” to be a movement that starts from the top of the head towards the front (usually) so that nodding at something would imply downward motion of the head towards the object. Even if someone is asleep, and the head tilts backwards, I’ve always heard that motion by itself to be called tilting, especially when it is to the sides. The collective nods and tilts can be called “nodding” (as in “nod off”).

As an old time “chin pointer,” I feel that chinpointing is virtually the opposite: although it is possible to point with hope chin without moving your head, there is generally a forward thrust of the chin, and a slight backwards tilt (see?) of the head to facilitate the pointing. I’ve heard it called “chin-pointing,” as “chin thrust” implies something more aggressive.

She chinpointed towards the car: “There it is!” she said. Her companion said, “You just pointed with your chin!” “Yes, I do it all the time!” she replied. [Actual incident happening to me last week]

I think 'nodding' will have to be taken to mean both up and down motion of the chin - that would solve the problem temporarily, until someone coins a word to describe exactly that gesture of pointing with one's chin. Chin-pointing is, I feel, a clumsy compound word and can itself be subjected to further hair-splitting as 'pointing' is generally assumed to be done with the forefinger.

Don't be alarmed if you see someone in the Philippines on the street pointing their lips at someone or something. ... Instead of lifting their finger or arm, Filipinos commonly use their lips to point to an object or another person. This gesture is called nguso, and shouldn't be taken as an invitation for a kiss!

The Culture Trip: Your Guide to Filipino Gestures