I had same problem but got it fixed by doing:

import {
 ValidateNested,
 IsDefined,
 IsNotEmptyObject,
} from 'class-validator';

import { Type } from 'class-transformer';
import { ApiProperty } from '@nestjs/swagger';

@IsDefined()
@IsNotEmptyObject()
@ValidateNested()
@ApiProperty()
@Type(() => AddressDto)
address: AddressDto;

Using this answer stackoverflow.com/a/53685045/4694994