I expect it should work:
```
:) select CAST(CAST('{"x" : 1}', 'Object(\'json\')'), 'Object(Nullable(\'json\'))')

SELECT CAST(CAST('{"x" : 1}', 'Object(\'json\')'), 'Object(Nullable(\'json\'))')

Query id: fb057b45-b72a-4d22-9b38-a3136cdf2465


0 rows in set. Elapsed: 0.002 sec.

Received exception from server (version 22.5.1):
Code: 53. DB::Exception: Received from localhost:9000. DB::Exception: Cast to Object can be performed only from flatten named Tuple, Map or String. Got: Object('json'): While processing CAST(CAST('{"x" : 1}', 'Object(\'json\')'), 'Object(Nullable(\'json\'))'). (TYPE_MISMATCH)
```

@CurtizJ what do you think?
return ret;
        if (callOnIndexAndDataType<void>(to_type->getTypeId(), make_default_wrapper))
            return ret;
        switch (to_type->getTypeId())
        {
            case TypeIndex::String:
                return createStringWrapper(from_type);
            case TypeIndex::FixedString:
                return createFixedStringWrapper(from_type, checkAndGetDataType<DataTypeFixedString>(to_type.get())->getN());
            case TypeIndex::Array:
                return createArrayWrapper(from_type, static_cast<const DataTypeArray &>(*to_type));
            case TypeIndex::Tuple:
                return createTupleWrapper(from_type, checkAndGetDataType<DataTypeTuple>(to_type.get()));
            case TypeIndex::Map:
                return createMapWrapper(from_type, checkAndGetDataType<DataTypeMap>(to_type.get()));
            case TypeIndex::Object:
                return createObjectWrapper(from_type, checkAndGetDataType<DataTypeObject>(to_type.get()));
            case TypeIndex::AggregateFunction:
                return createAggregateFunctionWrapper(from_type, checkAndGetDataType<DataTypeAggregateFunction>(to_type.get()));
            default:
                break;
        }
        if (cast_type == CastType::accurateOrNull)
            return createToNullableColumnWrapper();
        else
            throw Exception{"Conversion from " + from_type->getName() + " to " + to_type->getName() + " is not supported",
                ErrorCodes::CANNOT_CONVERT_TYPE};
    }
};
class MonotonicityHelper