Try the custom AI to help you find products that Reddit loves.
They make little humidifiers that will attach to a water bottle and therefore don't take up much luggage space. You can place it on your bedside table while you sleep.
IDK anything about this one specifically, but a cursory amazon search yields tons of decently priced results like this: https://smile.amazon.com/Pure-Enrichment-MistAire-Travel-Ultrasonic/dp/B07HCTYFLV/ref=sr\_1\_5?keywords=portable+humidifiers+for+travel&qid=1668014589&sprefix=portable+hum%2Caps%2C114&sr=8-5
Actually a great question because there are some nuances. A lot of the smaller humidifiers I've seen have an on/off button that needs to be pressed every time the humidity controller cycles so they would not work well for a chamber.
Conversely, the larger humidifiers with the dials take up a lot of real-estate in a smaller chamber (like a wine fridge for example).
I found this humidifier was perfect.
It has a dial so when it cycles on it will turn on, and you can use whatever size bottle. I use a 1L plastic bottle and need to refill it once every 10-15 days
Pure Enrichment MistAire Travel - Ultrasonic Cool Mist Water Bottle Humidifier with Auto Shut-Off, Mood Light, Fold-Out Leg, and Storage Bag for Portable Use at Home, Office, Hotel, and More https://www.amazon.com/dp/B07HCTYFLV/ref=cm_sw_r_cp_api_glt_fabc_NVCPTYHS6MQ96S58N9MY
Very small footprint, uses a normal pop/water bottle as the reservoir. I put a 1L water bottle on it. The little output "nozzle" wouldn't stay up for me (kept falling down) so I stuck a piece of adhesive-back velcro onto it under the outlet hole, which stops it from falling down
I looked at buying an ultrasonic mist-maker element and building the humidifier myself, but this costs basically the same but without the time to build and debug a DIY version
Thanks! I was able to find it on amazon. I think they sell it at Target as well. https://www.amazon.com/Pure-Enrichment-MistAire-Travel-Ultrasonic/dp/B07HCTYFLV