I hear this mistake a lot. My students fully pronounce the vowels in each syllable of chocolate. But American English speakers will reduce the syllables and reduce the vowel sound in the weaker syllable.
However, it’s pronounced a lot like CHOK lit (2 syllables) with the stress on the first syllable.
—-Since we don’t usually pronounce all three syllables, this is similar to when we reduce syllables from family(3 syllables) to say famlee(2 syllables) and interesting(4 syllables) to say intresting(3 syllables). —-
To pronounce chocolate like a North American:
Pronounce the o like “aw” (or “ah” if you note regional differences).
Drop out the middle syllable o.
Reduce the a in the last syllable “late” to /I/(short i) or /ə/(the schwa sound).
Keep up the good work speaking English