| 18 jul 2026 | Simacek, Pavel 2373 | Heldenbergh, Nils 2209 | 1-0 | A69 Defensa Benoni: Four Pawns Attack, Main Line | Czech Open 2026 | E | 28 | Ver |
| 23 may 2026 | Gloeckler, Christian 2497 | Heldenbergh, Nils 2212 | 1-0 | B30 Defensa Siciliana: Closed, Anti-Sveshnikov Variation | 18th BPB Limburg Open | Open | 59 | Ver |
| 3 abr 2026 | Heldenbergh, Nils 2222 | Draskovic, Luka 2489 | 0-1 | B61 Defensa Siciliana: Richter-Rauzer Variation, Modern Variation | Grenke Chess Festival 2026 Open | 53 | Ver |
| 3 ene 2026 | Marn, Jan 2386 | Heldenbergh, Nils 2190 | 1-0 | D30 Gambito de Dama rehusado: Tarrasch Defense, Pseudo-Tarrasch | 14th Chess Festival Palmanova 2025/2026 | 45 | Ver |
| 2 ene 2026 | Heldenbergh, Nils 2190 | Kanov, Nikola 2403 | 0-1 | B85 Defensa Siciliana: Scheveningen Variation, Classical Main Line | 14th Chess Festival Palmanova 2025/2026 | 57 | Ver |
| 1 ene 2026 | Yao, Lan 2307 | Heldenbergh, Nils 2190 | 0-1 | B56 Defensa Siciliana: Kupreichik Variation | 14th Chess Festival Palmanova 2025/2026 | 54 | Ver |
| 30 dic 2025 | Panelo, Marcelo 2318 | Heldenbergh, Nils 2205 | ½-½ | A04 Apertura Zukertort: Sicilian Invitation | 14th Chess Festival Palmanova 2025/2026 | 39 | Ver |
| 28 dic 2025 | Solodovnichenko, Yuri 2510 | Heldenbergh, Nils 2205 | 1-0 | B33 Defensa Siciliana: Lasker-Pelikan Variation, Sveshnikov Variation, Chelyabinsk Variation | 14th Chess Festival Palmanova 2025/2026 | 61 | Ver |
| 19 oct 2025 | Heldenbergh, Nils 2177 | Pijpers, Arthur 2487 | 0-1 | B34 Defensa Siciliana: Accelerated Dragon, Modern Variation | European Chess Club Cup 2025 | Open Matches 17+ | 29 | Ver |
| 14 sep 2025 | Signorelli, Gaetano 2210 | Heldenbergh, Nils 2168 | 1-0 | B30 Defensa Siciliana: Old Sicilian | Alma Mater University Chess Tournament | 47 | Ver |
| 13 sep 2025 | Heldenbergh, Nils 2168 | Belli, Giorgio 2206 | ½-½ | B90 Defensa Siciliana: Najdorf Variation | Alma Mater University Chess Tournament | 24 | Ver |
| 13 sep 2025 | Colonetti, Fabio 2151 | Heldenbergh, Nils 2168 | ½-½ | D30 Gambito de Dama rehusado: Tarrasch Defense, Pseudo-Tarrasch | Alma Mater University Chess Tournament | 44 | Ver |
| 12 sep 2025 | Ypma, Jord 2109 | Heldenbergh, Nils 2168 | ½-½ | D02 Apertura de Peón de Dama: London System, with e6 | Alma Mater University Chess Tournament | 52 | Ver |