Yes, I just did that and got the answer
Thank you so much @spinscale
Really appreciate your help on this one 
Answer for future readers:
"ctx.payload.aggregations.<first_agg>.buckets.0.<second_agg>.buckets.0.<field>"
// Example:
"ctx.payload.aggregations.managedobjectref.buckets.0.timerange.buckets.0.doc_count"
Note: This is when there is only ONE array