Most of the time, I associate Malaysian Chinese English with having more Cantonese loan words whereas we have more Hokkien. We also have different Malay loan words that are clear giveaways.
If someone says ‘wah they very atas’ where atas means ‘rich’ or ‘high class’, that’s usually a Singaporean
If someone says ‘wah syiok’ emphasis on the ‘sy’ instead of ‘schhhhiok’, that tells me they’re Malaysian