Chronica Feudalis makes the default assumption that all of the protagonists are all peasants (maybe even yeomen, if your setting is far enough in time) and suggests that if you're interested in some kind of status, you can add it via background. If you're wanting something with a little more swagger in your social status, then here are some optional rules you can try out.
Like everything that makes your character truly special or interesting, CF handles this aspects. While vanilla CF makes passing mention of a character with the Fearless Knight, the subject isn't strictly addressed in a broader social way. There are two distinct methods I'm going to use here, House Affiliation, and Status
House affiliation represents a character whom is a member of a specific noble family, whether they are the reigning lord (duke, etc), an heir or other family member. You can take this aspect directly (Scion of House Blackwell) or phrase it in such a way to imply reputation ("A Lannister always pays his debts.").
In addition to being able to invoke this aspect in any normal way (most often rolls to influence another party), you may also invoke your House aspect when making purchase rolls to represent letters of credit or resources tied up in your family holdings. Note however, that all of the rules that apply to the purse also apply to your House die, including the conditions for step reduction. This represents the loss of influence that comes as debts pile up and rumors fly ("Did you hear that the Blackwells had to sell off part of their lands to settle their son's tournament losses?"). A careless noble could spend his family into ruin.
If several characters belong to the same noble house, they share this Aspect. As the wealth and influence dwindles, it affects all of the characters with the die, rather than each individual separately. Aspect dice spent this way can't be raised at the end of the session as others can. Instead, they rely on the actions of the characters in the setting. If the letcherous son of Bywin Flannister begins to empty the family's coffers with whoremongering and folly, it may be up to the father to eliminate a rival or win political favor to restore the family name (and thus bring their die back up).
While not strictly nobility, players wishing to simulate rich merchant characters or others whose wealth and influence is otherwise tied up in lands or industry can use a similar approach.
Certain characters may not have access to land and wealth in the same fashion that some of the great houses do, but they may have some of the trappings of nobility all the same. Characters who can claim title or a badge of office ("Reeve of Curthshire," "Captain of the Debra Sanchez," "First Sword of Braavos") may take that trapping as an aspect. Many who were noble by blood placed themselves in the service of other nobles or the church, with no income of their own. Taking such aspects as Sworn Knight or Priest of Recursivous, The God of Priests can represent this well.
These aspects functions in nearly all ways similarly to the aspects as written in the core book, and may not be used to leverage wealth. However, they can still come with a prestige of their own and can be used to influence others. Characters wishing to do so should tread carefully, however. No matter how high your die, invoking your title against someone above your station will not only do you little good (invoking Priest of St. Cthulhu's Cathedral has no effect on the abbot, nor on the king), but may well provoke their wroth.