Elasticsearch - how to apply sort on nested field - elasticsearch

Question

I'm rewriting the nested field in the documents and failing to get the query right to sort on the nested fields.
Previously I had the nested field like this:
"my_nested_obj": {
"project-type": [
{
"name": "Table",
"value": "159841"
}
],
"cost": [
{
"name": "Under $50",
"value": "426503"
}
],
"skill-level": [
{
"name": "Intermediate",
"value": "63897"
}
],
"room": [
{
"name": "Outdoor",
"value": "19246"
}
]
}....
And I was able to write queries like these where I can boost and also sort on the 'my_nested_obj' for example:
{
"from": 0,
"size": 50,
"query": {
"filtered": {
"query": {
"multi_match": {
"query": "something",
"fields": [
"content",
"name",
"my_nested_obj.skill-level.name^3"
]
}
},
"filter": {
"bool": {
"must": [
{
"match_all": [
]
},
{
"term": {
"retired": false
}
}
]
}
}
}
},
"sort": {
"my_nested_obj.skill-level.name": "desc"
},
"timeout": "1800ms"
}
Now, I need to reformat the nested field like:
"my_nested_obj": [
{
"name": "Table",
"type": "project-type",
"value": "159841"
},
{
"name": "Under $50",
"type": "cost",
"value": "426503"
},
{
"name": "Intermediate",
"type": "skill-level",
"value": "63897"
},
{
"name": "Outdoor",
"type": "room",
"value": "19246"
}
]....
I can do a generic sort on my_nested_obj.name like:
....
"sort": {
"my_nested_obj.name": "desc"
},
...
How do I go about adding for example sort specifically skill-level name and not all the my_nested_obj.name? Also is there some way to specify the boost?
Thanks!