She met the Queen at the Palace of Holyroodhouse on Wednesday alongside Scottish Parliament Presiding Officer Alison Johnstone, just 24 hours after the SNP leader revealed plans for a second Scottish independence referendum next October.
Former Northern Ireland First Minister Arlene Foster tweeted about the recent royal interaction and said that meeting the Queen was one of the “greatest privileges” she had during her role within the Northern Ireland Executive.
She tweeted: "Why did’t [sic] she curtsy?? It was one of the greatest privileges I had as FM of NI to curtsy to members of the royal household including HM the Queen."
Some Twitter users hit back at the GB News presenter’s accusations on the interaction.
One said: “Because its respectful to both parties but not subservient. You see Nicola like most normal self-respecting people knows we are all equal and that no one human or group is any more entitled than another.”
Said another: “It’s not obligatory. When the Queen was in Belfast several years ago and met lots of local people in St Georges Market no one was required, asked or obliged to curtsy to her, including me. We had a rehearsal the day before and all this was discussed,” said another, while one person said it was an “anachronistic and clumsy” gesture.
“Because its an anachronistic and clumsy gesture that has no place in the modern world. In case you haven't noticed (you haven't have you?) this is the twenty-first century,” added another.
The Royal Family's website states that curtsying is not “obligatory” when meeting the Queen or a member of a the royal family.
"There are no obligatory codes of behaviour when meeting The Queen or a member of the Royal Family, but many people wish to observe the traditional forms. For men this is a neck bow (from the head only) whilst women do a small curtsy. Other people prefer simply to shake hands in the usual way.
"On presentation to The Queen, the correct formal address is 'Your Majesty' and subsequently 'Ma'am,' pronounced with a short 'a,' as in 'jam'. For male members of the Royal Family the same rules apply, with the title used in the first instance being 'Your Royal Highness' and subsequently 'Sir'.
"For other female members of the Royal Family the first address is conventionally 'Your Royal Highness' and subsequently 'Ma'am'."