main.swift

import Foundation

let jsonData = try! Data(contentsOf: Bundle.main.url(forResource: "stats", withExtension: "json")!)
let teamStats = try! JSONDecoder().decode(TeamStats.self, from: jsonData).elements

stats.json

{
  "overallteamstandings": {
    "lastUpdatedOn": "2017-12-10 2:29:19 AM",
    "teamstandingsentry": [{
        "team": {
          "ID": "109",
          "City": "Houston",
          "Name": "Rockets",
          "Abbreviation": "HOU"
        },
        "rank": "1",
        "stats": {
          "GamesPlayed": {
            "@abbreviation": "G",
            "#text": "24"
          },
          "Wins": {
            "@category": "Standings",
            "@abbreviation": "W",
            "#text": "20"
          },
          "Losses": {
            "@category": "Standings",
            "@abbreviation": "L",
            "#text": "4"
          }
        }
      },
      {
        "team": {
          "ID": "82",
          "City": "Boston",
          "Name": "Celtics",
          "Abbreviation": "BOS"
        },
        "rank": "2",
        "stats": {
          "GamesPlayed": {
            "@abbreviation": "G",
            "#text": "27"
          },
          "Wins": {
            "@category": "Standings",
            "@abbreviation": "W",
            "#text": "22"
          },
          "Losses": {
            "@category": "Standings",
            "@abbreviation": "L",
            "#text": "5"
          }
        }
      },
      {
        "team": {
          "ID": "101",
          "City": "Golden State",
          "Name": "Warriors",
          "Abbreviation": "GSW"
        },
        "rank": "3",
        "stats": {
          "GamesPlayed": {
            "@abbreviation": "G",
            "#text": "27"
          },
          "Wins": {
            "@category": "Standings",
            "@abbreviation": "W",
            "#text": "21"
          },
          "Losses": {
            "@category": "Standings",
            "@abbreviation": "L",
            "#text": "6"
          }
        }
      }
    ]
  }
}

TeamStats.swift

import Foundation

struct TeamStats {
    let elements: [TeamStat]
}

extension TeamStats: Decodable {
    enum CodingKeys: String, CodingKey {
        case overallteamstandings
    }
    
    enum OATSKeys: String, CodingKey {
        case teamstandingsentry
    }
    
    public init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: CodingKeys.self)
        let oats = try values.nestedContainer(keyedBy: OATSKeys.self, forKey: .overallteamstandings)
        self.elements = try oats.decode([TeamStat].self, forKey: .teamstandingsentry)
    }
}

struct TeamStat {
    let city: String
    let name: String
    let wins: String
    let losses: String
}

extension TeamStat: Decodable {
    enum CodingKeys: String, CodingKey {
        case team, stats
    }
    
    enum TeamKeys: String, CodingKey {
        case city = "City"
        case name = "Name"
    }
    
    enum StatsKeys: String, CodingKey {
        case wins = "Wins"
        case losses = "Losses"
    }
    
    enum WinsLossesKeys: String, CodingKey {
        case text = "#text"
    }
    
    public init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: CodingKeys.self)
        
        let team = try values.nestedContainer(keyedBy: TeamKeys.self, forKey: .team)
        self.city = try team.decode(String.self, forKey: .city)
        self.name = try team.decode(String.self, forKey: .name)
        
        let stats = try values.nestedContainer(keyedBy: StatsKeys.self, forKey: .stats)
        let wins = try stats.nestedContainer(keyedBy: WinsLossesKeys.self, forKey: .wins)
        self.wins = try wins.decode(String.self, forKey: .text)
        let losses = try stats.nestedContainer(keyedBy: WinsLossesKeys.self, forKey: .losses)
        self.losses = try losses.decode(String.self, forKey: .text)
    }
}