Right
查 supplies the sound (chá → zhā, retroflex shift).
查 standalone means 'examine,' but here it contributes no semantics.
喳 is onomatopoeic:
叽叽喳喳 chirping/chattering of small birds, or
喳喳 a hushed whisper. The doubled form is by far the most common usage, capturing the patter of small repeated sounds.