Yes, you can typically eat kimchi that has been left in the fridge overnight. In fact, kimchi is a fermented food, and the fermentation process helps to preserve it for an extended period. Leaving kimchi out at room temperature for an extended period could lead to it spoiling, but when stored in the refrigerator, it can stay safe to eat for several days, even weeks, depending on its initial freshness and the conditions of your fridge.
The overnight period should not pose any significant safety concerns for kimchi. In fact, many people find that kimchi's flavors become more developed and complex as it ferments over time. However, the taste and texture of kimchi may change over a few days in the refrigerator, and it may become more sour and softer as the fermentation process continues.
If you notice any unusual odors, colors, or signs of mold growth on the kimchi, it's best to discard it, as these could indicate spoilage. Otherwise, if it looks and smells fine, it should be safe to consume.
As with any food, it's essential to use proper food safety practices. Make sure to keep the kimchi covered and stored in a sealed container in the refrigerator to maintain its quality and prevent any cross-contamination with other foods.