Você pode usar
$expr
Location.aggregate([
{ "$geoNear": {
"spherical": true,
"near": { "type": "Point", "coordinates": [ user.location.coordinates[0], user.location.coordinates[1] ] },
"distanceField": "dist.calculated"
}},
{ "$match": { "$expr": { "$lte": ["$distanceField", "$distance"] }}}
])
