| ITF China F11 Qual | 07/01 05:10 | 62 | Stefan Vujic v Kazuki Nishiwaki | Retired | |
| ITF Guam F1 | 06/20 06:00 | 25 | Kazuki Nishiwaki v Ju-Hae Moon | 2-6,1-6 | |
| ITF Guam F1 | 06/17 23:00 | 54 | Kazuki Nishiwaki v Kennosuke Nouchi | 6-2,6-2 | |
| ITF Japan F8 | 06/12 00:00 | 62 | Keisuke Watanuki v Kazuki Nishiwaki | 6-2,6-2 | |
| ITF Japan F8 | 06/11 00:00 | 62 | James Trotter v Kazuki Nishiwaki | 6-7,4-6 | |
| ITF Japan F8 | 06/10 04:00 | 62 | Kenta Kurita v Kazuki Nishiwaki | 1-6,5-7 | |
| ITF Singapore F2 Qual | 05/28 04:00 | 54 | Kazuki Nishiwaki v Ken Onoda | 5-7,6-1,1-6 | |
| ITF Singapore F1 | 05/26 02:00 | 26 | Kazuki Nishiwaki v Nam Hoang Ly | Walkover | |
| ITF Singapore F1 | 05/25 02:00 | 25 | Issei Okamura v Kazuki Nishiwaki | 6-7,1-6 | |
| ITF Singapore F1 Qual | 05/22 06:10 | 54 | Kazuki Nishiwaki v Vignesh Peranamallur | 6-1,6-1 | |
| ITF Singapore F1 Qual | 05/21 04:00 | 54 | Yu Hsiang Chiu v Kazuki Nishiwaki | 0-6,2-6 | |
| ITF Japan F5 | 04/03 05:00 | 25 | Kazuki Nishiwaki v Tung-Lin Wu | 3-6,5-7 | |
| ITF Japan F5 | 04/02 01:00 | 54 | Tomohiro Masabayashi v Kazuki Nishiwaki | 1-6,6-7 | |
| ITF Japan F5 | 04/01 01:00 | 54 | Yuto Sakai v Kazuki Nishiwaki | 2-6,6-7 | |
| ITF Japan F4 | 03/25 02:00 | 62 | Yuki Matsuo v Kazuki Nishiwaki | 5-7,7-6,6-3 | |
| ITF Japan F3 | 03/19 01:00 | 62 | Sho Shimabukuro v Kazuki Nishiwaki | 6-3,7-5 | |
| ITF Japan F3 | 03/18 08:00 | 62 | Kazuki Nishiwaki v Zhaoyi Cao | 6-3,6-0 | |
| ITF Japan F3 | 03/18 00:30 | 62 | Kazuki Nishiwaki v Kaito Itsusaki | 6-3,6-4 | |
| ITF China F3 Qual | 02/26 03:40 | 62 | Jun Nan Tao v Kazuki Nishiwaki | 6-3,6-2 | |
| ITF China F3 Qual | 02/25 03:00 | 62 | Kazuki Nishiwaki v Sheng Hao Zhou | 2-6,7-6,7-5 | |
| ITF China F2 Qual | 02/18 02:40 | 62 | Kazuki Nishiwaki v Jun Nan Tao | 4-6,3-6 | |
| ITF W60 Montpellier | 11/05 04:05 | 45 | Kazuki Nishiwaki v Kento Takeuchi | 0-6,2-6 | |
| ITF Japan F8 | 06/16 02:50 | 26 | Gengo Kikuchi v Kazuki Nishiwaki | 7-6,6-4 | |
| ITF Japan F8 | 06/15 04:30 | 25 | Kazuki Nishiwaki v Hiromasa Oku | 2-6,6-3,6-4 | |
| ITF Japan F4 | 03/28 00:30 | - | Yutaro Matsuzaki v Kazuki Nishiwaki | 6-7,6-4,6-4 | |
| ITF Japan F2 | 03/14 00:30 | - | Ryota Tanuma v Kazuki Nishiwaki | 6-4,6-4 | |
| ITF Japan F6 Qual | 06/09 03:00 | - | Shohei Chikami v Kazuki Nishiwaki | 6-0,6-3 | |
| ITF Japan F5 | 06/04 03:35 | - | Kazuki Nishiwaki v Jui-Chen Hung | 4-6,6-7 | |
| ITF Japan F5 | 06/03 01:00 | - | Shunrou Takeshima v Kazuki Nishiwaki | 6-3,5-7,3-6 |