Object to pass to Nested as missing

In deserialization, It seems like the `missing` value is what is returned if there is no value as opposed to the value that gets passed to the nested Schema. Is there anyway to have "default" value for the nested schema?
e.g:
```python
class A(Schema):
a = fields.String()

class B(Schema):
b = fields.Nested(A, many=True, missing=[])

class C(Schema):
c = fields.Nested(B, missing={})

C().load({}) # returns {'c': {}}
```
I would like it to return `{'c': {'b': []}}`, i.e have it run the nested schema passing an empty object and then letting the nested schema apply its own missing logic.

Start by tracing marshmallow's Nested deserialization and missing-value handling, using the C/B/A example as the reproduction. Determine how a missing nested value should trigger the inner schema's missing behavior, then add coverage showing C().load({}) produces the requested nested result.

Written by the indexing model from the issue text.