[{"_id":"5ffc130e9fb31b26162e0bad","results":[{"customer":{"display_name":"Manno Dispensary - first","ext_acct_id":"267"}},{"customer":{"display_name":"Manno Dispensary - second","ext_acct_id":"262"}},{"customer":{"display_name":"Kako Dispensary - first","ext_acct_id":"261"}},{"customer":{"display_name":"Kako Dispensary - second","ext_acct_id":"263"}}]}]

db.collection.find({results:{$elemMatch:{"customer.display_name":{$regex:"Manno"}}}},{results:{$filter:{input:"$results",cond:{$regexMatch:{input:"$$this.customer.display_name",regex:"Manno"}}}}})