| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. H Nielsen vs H Opsahl |
| 1-0 | 57 | 1950 | Dubrovnik Olympiad | C86 Ruy Lopez, Worrall Attack |
| 27. B Rabar vs H Nielsen |
| 1-0 | 35 | 1950 | Dubrovnik Olympiad | D51 Queen's Gambit Declined |
| 28. H Nielsen vs S Lindquist |
| 0-1 | 52 | 1950 | Dubrovnik Olympiad | D47 Queen's Gambit Declined Semi-Slav |
| 29. Boulachanis vs H Nielsen |
 | 0-1 | 28 | 1950 | Dubrovnik Olympiad | A46 Queen's Pawn Game |
| 30. H Nielsen vs Larsen |
| 1-0 | 55 | 1953 | Copenhagen Championship | E33 Nimzo-Indian, Classical |
| 31. Larsen vs H Nielsen |
| 1-0 | 21 | 1955 | Danish Championship | E09 Catalan, Closed |
| 32. H Nielsen vs Larsen |
| 0-1 | 63 | 1959 | DEN-ch | A40 Queen's Pawn Game |
| 33. F Petersen vs H Nielsen |
| 0-1 | 55 | 1960 | Danish Championship | C86 Ruy Lopez, Worrall Attack |
| 34. H Nielsen vs E Pedersen |
| 0-1 | 25 | 1960 | Danish Championship | C64 Ruy Lopez, Classical |
| 35. B Kolvig vs H Nielsen |
| 1-0 | 22 | 1960 | Danish Championship | B50 Sicilian |
| 36. H Nielsen vs E Jensen |
| 1-0 | 32 | 1960 | Danish Championship | D44 Queen's Gambit Declined Semi-Slav |
| 37. H Nielsen vs V J Hansen |
| 1-0 | 62 | 1960 | Danish Championship | A37 English, Symmetrical |
| 38. H Nielsen vs J Enevoldsen |
| 0-1 | 42 | 1960 | Danish Championship | B75 Sicilian, Dragon, Yugoslav Attack |
| 39. A Nielsen vs H Nielsen |
| 1-0 | 41 | 1960 | Danish Championship | A22 English |
| 40. H Nielsen vs S Hamann |
| ½-½ | 44 | 1960 | Danish Championship | A80 Dutch |
| 41. T Haahr vs H Nielsen |
| ½-½ | 66 | 1960 | Danish Championship | E14 Queen's Indian |
| 42. H Nielsen vs K Blom |
| 1-0 | 61 | 1960 | Danish Championship | B45 Sicilian, Taimanov |
| 43. S From vs H Nielsen |
| 1-0 | 49 | 1960 | Danish Championship | B02 Alekhine's Defense |
| 44. E Pedersen vs H Nielsen |
| 1-0 | 63 | 1961 | DEN-ch | E73 King's Indian |
| 45. H Nielsen vs T Haahr |
| 1-0 | 42 | 1961 | Ch Denmark | C27 Vienna Game |
Kibitzing
