With Nantucket red chinos, or any other bright and bold summer pant, I generally trend away from adding a tie. The pants are enough on their own, more often than not, no tie is needed. In this case I made an exception and it works wonderfully, even if threading the needle a bit.
Part of the reason this works well in the way I am approaching the outfit is the casual nature of the tie. Nantucket red chinos already carry such a particular feeling with them. Summer, holiday, relaxed. This is part of the reason why just a simple white OCBD or blue university stipe works so well with them, tucked or untucked. The same goes for boat shoes paired with the reds.
The entire feeling and vibe of this Nantucket red is one that feels so summery and relaxed that trying to make them strictly "formal" can end up feeling disjointed. It can be done of course, but it can be a narrow path. Adding a tie to any outfit automatically pushes you in a more formal direction so doing so in this case needs to be done carefully.
When adding a tie, knit ties always help bring the formality down. So, if you want to keep the formality as low as possible, while adding a tie, the knit tie the naturally a clear choice. In this case I am wearing a navy knit tie with blue and white stripes. In order to downplay the formality further, I am also wearing the shirt with both collar buttons unbuttoned.
This is a polarizing choice. Some people hate this look and don't understand why you would unbutton buttons that are clearly meant to be buttoned, they say it is slobbish. Some people like this look and feel that it adds a certain level of casual natural elegance in a semi-sprezzatura manner. Everyone has their own taste. Sometimes I like this look, sometimes I don't. It all depends on the setting.
In this case, where we are riding on the edge of casual vs formal, work vs play, serious vs relaxed, the contradictions that are found throughout the outfit push the essence in different directions in different ways while keeping the feeling right in a strange space of hard to pin down style. In many ways this is a classic Ivy result. Dressed up casual and dressed down formal. In a space it's own.