I'm going to grill the chicken a day or two ahead of the event and want to park it in the boiled, cooled marinade so it doesn't dry out.
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amysarah is a trusted home cook.
First, if you're using the marinade to serve the chicken, boil it down very well. Raw chicken juices are no one's friend! But I think I'd store the chicken separately from the marinade. (Well wrapped, it should be fine.) Depending on its ingredients - especially acidic ones - a marinade can break down meat fiber and effect its texture. You can use the boiled down marinade as a glaze to drizzle over the chicken when you serve it.
Good thoughts. Thanks very much.